Bluetooth Signal Jamming in Linux Mint 22.1: Mouse Interference Blocks Audio Device Detection On Linux Mint 22.1 with PipeWire, I ran into an odd issue with Avantree Bluetooth headphones. They paired successfully (bluetoothctl showed them as connected), but no audio sink appeared in pavucontrol, pactl list sinks, or Mint’s sound settings—no sound output at all. After a lot of trial and error, I traced the problem to Bluetooth interference from a wireless mouse. It was paired, energized, and idle. Once I disconnected the mouse, the headphones instantly appeared as an audio device and started working as expected. Summary: PipeWire was set up correctly, PulseAudio removed Headphones paired successfully but weren't usable Disconnecting an unused Bluetooth mouse allowed audio routing to work This appears to be low-level Bluetooth bandwidth interference, where idle devices can block others from establishing full functionality—even if they’re not actively being used. If you’re troubleshooting missing Bluetooth audio sinks, try disconnecting unused peripherals first. It may save hours of frustration.

I have an ssh server running Kubuntu 22.04 behind a router providing internet connection, but without a public IP (this is the policy of the ISP). So, the server can access the internet, but any port mapping between the router and the ssh server is useless, so the server is not directly accessible from the internet. I would like instead to be able to access the server via ssh from another internet host. If possible, I would like to do this without spending money. Is there a way to accomplish this? ---------- As correctly guessed in the comments, the ssh server is behind a CGNAT, so its router has no public IP address and is not reachable.

I'm running Ubuntu 18.04 LTS on an MSI GS65 Stealth 8RE . When the laptop gets out of sleep mode, air plane mode is on and Linux says it must be deactivated via a physical switch. The FN+F10 combination to turn it off works on Windows, but doesn't on Ubuntu. When I reboot, everything seems to be fine. So it's not too bad, but systematic and very annoying nonetheless. I have the usual rfkill output : ubuntu@ubuntu:~$ rfkill list all 0: phy0: Wireless LAN Soft blocked: no Hard blocked: yes

I'm trying to use Palo GlobalProtect VPN to connect to some VPN server. The connection attempt is stuck at "looking for portal". What could the issue be? I use Kubuntu 24.04.1 LTS. That works fine on Windows 10 21H2 Pro, so the VPN server is alive. --- From PanGPS.log:

P1004-T-488634688 02/03/2025 10:11:39:744 Debug(2092): Send response to client for request portal
P1004-T-648018240 02/03/2025 10:12:09:673 Debug( 370): WAIT_TIMEOUT
P1004-T-648018240 02/03/2025 10:12:09:673 Debug( 727): HipMonitorThread quits.

Full log:

P 982-T944278400 02/03/2025 10:24:30:275 Debug( 336): PanGPS, working directory is /opt/paloaltonetworks/globalprotect/
P 982-T944278400 02/03/2025 10:24:30:291 Info ( 539): ####################### Start PanGPS service (ver: 6.1.5-715) #######################
P 982-T944278400 02/03/2025 10:24:30:291 Info ( 540): Debug level is 5, log path is /opt/paloaltonetworks/globalprotect/
P 982-T944278400 02/03/2025 10:24:30:292 Info ( 541): User is (null), home is /root, login is (null)
P 982-T944278400 02/03/2025 10:24:30:292 Info ( 150): Predeployed log-path-service is not set
P 982-T944278400 02/03/2025 10:24:30:296 Info ( 439): Get OS info: Ubuntu 24.04.1 LTS
P 982-T944278400 02/03/2025 10:24:30:743 Debug( 464): Serial number is [HIDDEN]
P 982-T944278400 02/03/2025 10:24:30:831 Debug( 107): IsDaemon is 1
P 982-T944278400 02/03/2025 10:24:30:878 Info ( 121): PrelogonEnabled is 0
P 982-T944278400 02/03/2025 10:24:30:878 Info ( 504): cannot open /var/run/PanGPS.pid, assume no old instance running
P 982-T935331520 02/03/2025 10:24:30:878 Info ( 687): debug thread starts
P 982-T944278400 02/03/2025 10:24:31:095 Debug( 285): stopping split tunnel feature!
P 982-T944278400 02/03/2025 10:24:31:095 Debug(  27): split tunnel script dir /opt/paloaltonetworks/globalprotect/network/config
P 982-T944278400 02/03/2025 10:24:31:108 Debug( 397): Uninstalling iptables DNS chain...
P 982-T944278400 02/03/2025 10:24:32:681 Debug(  27): split tunnel script dir /opt/paloaltonetworks/globalprotect/network/config
P 982-T944278400 02/03/2025 10:24:32:682 Debug( 459): Uninstalling iptables Split Tunnel chain & routing tables...
sh: 1: realm: not found
P 982-T944278400 02/03/2025 10:24:33:894 Debug( 306): split tunnel stopped!
P 982-T944278400 02/03/2025 10:24:33:894 Debug(  61): psv init called
P 982-T944278400 02/03/2025 10:24:33:935 Info (2458): CPanMSServiceLinux::findJoinDomain: szDomainName is : 
P 982-T944278400 02/03/2025 10:24:33:935 Debug(  69): PanMSServiceLinux:ctor: m_szJoinDomain , m_szJoinDomainRaw 
P 982-T944278400 02/03/2025 10:24:33:935 Debug(  72): PanMSServiceLinux:ctor: m_domainName , m_domainNameRaw 
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 685): Service-only is no
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 757): Kerberos auth, stopOnKerberosFail=0()
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 762): Prefer ipv6 is yes.
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 785): CPanMSService::Init connect timeout 5, received timeout 30, portal timeout 5 
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 822): CPanMSService::Init fips: fipsc-cc-mode-enabled  
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 832): CPanMSService::Init enable-fips-cc-mode  
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 843): CPanMSService::Init fips: m_bFipsModeRequired 0 
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 238): GetValueBinary size 6
P 982-T944278400 02/03/2025 10:24:33:943 Debug( 921): Mac address is [HIDDEN]
P 982-T944278400 02/03/2025 10:24:33:943 Debug(2416): pan_get_gp_user_agent szGpUserAgent ua is PAN GlobalProtect/6.1.5-715 (Linux Ubuntu 24.04.1 LTS).
P 982-T944278400 02/03/2025 10:24:33:943 Info (10935): CheckPrelogon: Portal is , PrelogonEnabled is no
P 982-T944278400 02/03/2025 10:24:34:027 Debug( 971): override-cc-username is no
P 982-T944278400 02/03/2025 10:24:34:029 Debug(5151): event log file is /opt/paloaltonetworks/globalprotect//pan_gp_event.log
P 982-T944278400 02/03/2025 10:24:34:030 Debug( 981): Event log thread started
P 982-T944278400 02/03/2025 10:24:34:030 Debug( 167): Time zone GMT offset is -480
P 982-T924845760 02/03/2025 10:24:34:030 Debug(5120): event log thread started.
P 982-T944278400 02/03/2025 10:24:34:034 Info (10824): Portal config does not exist, try registry/plist
P 982-T944278400 02/03/2025 10:24:34:034 Debug( 354): default cert path is /etc/ssl/certs
P 982-T944278400 02/03/2025 10:24:34:034 Debug( 379): default private key path is /etc/ssl/private
P 982-T944278400 02/03/2025 10:24:34:034 Debug(1485): cfg no client cert.
P 982-T944278400 02/03/2025 10:24:34:034 Debug( 259): DLSA- agent is enable, restore lar during start up
P 982-T944278400 02/03/2025 10:24:34:034 Debug( 261): DLSA- Pan LAR file is /opt/paloaltonetworks/globalprotect/pan_lar.dat
P 982-T944278400 02/03/2025 10:24:34:035 Debug( 266): LAR file does not exist. 
P 982-T944278400 02/03/2025 10:24:34:035 Debug(  72): CControlManagerLinux::StartServer() isFipsModeRequired() 0
P 982-T944278400 02/03/2025 10:24:34:035 Debug( 554): Start tunnel driver.
P 982-T944278400 02/03/2025 10:24:34:038 Info ( 114): Service callback table gets set.
P 982-T944278400 02/03/2025 10:24:34:038 Debug( 231): set virtual interface driver started as yes
P 982-T944278400 02/03/2025 10:24:34:038 Debug( 592): Virtual interface is started
P 982-T903874240 02/03/2025 10:24:34:038 Info ( 102): Start ServerThread
P 982-T903874240 02/03/2025 10:24:34:038 Info (  71): It is running in Ubuntu.
P 982-T903874240 02/03/2025 10:24:34:038 Debug(10961): CPanMSService::StartPrelogonThread DaemonProcess: yes, InPrelogon: no
P 982-T903874240 02/03/2025 10:24:34:038 Debug(13545): Enforcer is not enabled
P 982-T914360000 02/03/2025 10:24:34:049 Debug( 440): RecvThread started.
P 982-T903874240 02/03/2025 10:24:44:672 Info ( 202): New Connection(127.0.0.1:34552) with socket(6)
P 982-T903874240 02/03/2025 10:24:44:672 Debug( 280): Checking connected App begin ...
P 982-T903874240 02/03/2025 10:24:45:205 Debug( 308): Connected by PanGPA from GP folder
P 982-T903874240 02/03/2025 10:24:45:205 Debug(1684): PanGPA pid 1423, uid 1000, gid 1000
P 982-T903874240 02/03/2025 10:24:45:205 Debug( 321): CPanListenerLinux::InitialConnectionTasks: Performing initial tasks upon GPA connection
P 982-T903874240 02/03/2025 10:24:45:384 Debug( 296): Checking connected App completed.
P 982-T903874240 02/03/2025 10:24:45:389 Info ( 542): msgtype = portal
P 982-T903874240 02/03/2025 10:24:45:389 Debug(2778): ----Portal Processing starts----
P 982-T903874240 02/03/2025 10:24:45:389 Debug(2808): User profile type is 0(not roaming)
P 982-T903874240 02/03/2025 10:24:45:391 Debug(2841): pg, source = 0, old source is 0
P 982-T903874240 02/03/2025 10:24:45:391 Debug(2863): pg, preferred gateway not set in message, old prefergateway=:)
P 982-T903874240 02/03/2025 10:24:45:391 Debug(2921): CheckUpdate is false.
)P 982-T903874240 02/03/2025 10:24:45:391 Debug(2936): portal-certificate-verification is yes
P 982-T903874240 02/03/2025 10:24:45:391 Debug(2993): No saml-load-cache tag.
P 982-T903874240 02/03/2025 10:24:45:391 Debug(3016): no saml-auth-error tag.
P 982-T903874240 02/03/2025 10:24:45:391 Debug(3029): allow-cached-portal is yes
P 982-T903874240 02/03/2025 10:24:45:391 Debug(3072): NewWinUser is f, WinUser is , PreviousSwitchOffMsg is false
P 982-T903874240 02/03/2025 10:24:45:391 Debug(3074): GetPrelogonStatus() 0, m_userName , m_preUsername 
P 982-T903874240 02/03/2025 10:24:45:391 Debug(3932): Grace period is 0
P 982-T903874240 02/03/2025 10:24:45:391 Debug(7391): StopThreads starts:
P 982-T903874240 02/03/2025 10:24:45:391 Debug(7394): threads have already stopped, StopThreads ends.
P 982-T903874240 02/03/2025 10:24:45:391 Debug(7355): StartThreads starts:
P 982-T893388480 02/03/2025 10:24:45:391 Debug(5624): CaptivePortalDetectionThread: captive portal detection thread starts.
P 982-T893388480 02/03/2025 10:24:45:391 Debug(5789): CaptivePortalDetectionThread: wait (-1 ms) for captive portal detection event.
P 982-T882902720 02/03/2025 10:24:45:391 Debug(5970): NetworkDiscoverThread: network discover thread starts.
P 982-T882902720 02/03/2025 10:24:45:391 Debug(5998): NetworkDiscoverThread: wait for fed mandate event.
P 982-T792725184 02/03/2025 10:24:45:391 Debug(6985): NetworkConnectionMonitorThread: network connection monitor thread starts.
P 982-T761267904 02/03/2025 10:24:45:391 Debug(1690): RouteReadThread entered.
P 982-T771753664 02/03/2025 10:24:45:392 Debug( 176): Start HipMissingPatchThread
P 982-T771753664 02/03/2025 10:24:45:392 Debug( 407): HipMissingPatchThread started...
P 982-T782239424 02/03/2025 10:24:45:392 Debug( 167): Start HipCheckThread
P 982-T782239424 02/03/2025 10:24:45:392 Debug( 210): HipCheckThread started...
P 982-T782239424 02/03/2025 10:24:45:392 Debug( 216): HipCheckThread: wait for hip check event for 3600000 ms);
P 982-T903874240 02/03/2025 10:24:45:392 Debug(3104): Update GP disable status to false
P 982-T803210944 02/03/2025 10:24:45:392 Debug(6687): HipReportThread: HipReportThread starts up.
P 982-T803210944 02/03/2025 10:24:45:392 Debug(6713): HipReportThread: wait for HIP report ready event.
P 982-T750782144 02/03/2025 10:24:45:393 Debug( 186): Start HipMonitorThread
P 982-T750782144 02/03/2025 10:24:45:393 Info ( 723): HipMonitorThread starts
P 982-T903874240 02/03/2025 10:24:45:395 Info (  49): It is running in Ubuntu.
P 982-T903874240 02/03/2025 10:24:45:395 Debug(11569): Saved password is empty.
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3301): Portal , user ___empty_username___, logonDomain , saved user , path /home/dernoncourt/.GlobalProtect/
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3368): use proxy is 1
P 982-T903874240 02/03/2025 10:24:45:395 Debug(11586): SSO password is empty
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3564): m_preUsername 
P 982-T903874240 02/03/2025 10:24:45:395 Debug(11546): Password is empty.
P 982-T903874240 02/03/2025 10:24:45:395 Debug(8676): Empty user for GetCachedPortalCfgOldNewFileName
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3584): CheckCachedPortalForPrelogon 0, PrelogonNeedTimeout 0, RenameTimeout -1, userName ___empty_username___, preUsername 
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3773): Use ssl tunnel is no
P 982-T903874240 02/03/2025 10:24:45:395 Debug(3783): bCheckCachedPortalForPrelogon: 0, m_bOnDemand: 0
P 982-T903874240 02/03/2025 10:24:45:395 Debug(7519): --Set state to Retrieving configuration...
P 982-T903874240 02/03/2025 10:24:45:444 Debug(8733): pszPortal is empty. Returns false.
P 982-T903874240 02/03/2025 10:24:45:444 Debug(7519): --Set state to Disconnected
P 982-T903874240 02/03/2025 10:24:45:447 Debug(2092): Send response to client for request portal
P 982-T750782144 02/03/2025 10:25:15:394 Debug( 370): WAIT_TIMEOUT
P 982-T750782144 02/03/2025 10:25:15:394 Debug( 727): HipMonitorThread quits.

For some weeks now, I have a Dell XPS 13 2022 with the following network card : Intel Alder Lake-P PCH CNVi WiFi

$ lshw -C network
 *-network
       description: Interface réseau sans fil
       produit: Alder Lake-P PCH CNVi WiFi
       fabriquant: Intel Corporation
       identifiant matériel: 14.3
       information bus: pci@0000:00:14.3
       nom logique: wlp0s20f3
       version: 01
       numéro de série: a0:02:a5:9e:9d:41
       bits: 64 bits
       horloge: 33MHz
       fonctionnalités: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=6.6.59_1 firmware=83.e8f84e98.0 so-a0-gf-a0-83.uc ip=192.168.1.47 latency=0 link=yes
multicast=yes wireless=IEEE 802.11
       ressources: mémoireE/S:600-5ff irq:16 mémoire:607a294000-607a297fff

And since the beginning, I have a very unstable connectivity. I use the same SSID/router/software to connect to WI-FI (actually wpa_cli) than my previous laptop, on the same GNU/Linux distrib (void linux) and in the previous one I had no issues like this. It disconnects randomly, and take a long time of trials and errors before catching a connection again. Here is a sample of the wpa_cli output :

CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-STARTED
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-STARTED
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-SSID-REENABLED id=2 ssid="Pretty Fly for A WI-FI"
Added BSSID f4:ca:e5:e6:01:a0 into ignore list, ignoring for 10 seconds
SME: Trying to authenticate with f4:ca:e5:e6:01:a0 (SSID='Pretty Fly for A WI-FI' freq=2462 MHz)
Trying to associate with f4:ca:e5:e6:01:a0 (SSID='Pretty Fly for A WI-FI' freq=2462 MHz)
Associated with f4:ca:e5:e6:01:a0
CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
CTRL-EVENT-DISCONNECTED bssid=f4:ca:e5:e6:01:a0 reason=7
BSSID f4:ca:e5:e6:01:a0 ignore list count incremented to 2, ignoring for 10 seconds
CTRL-EVENT-SSID-TEMP-DISABLED id=2 ssid="Pretty Fly for A WI-FI" auth_failures=3 duration=49 reason=CONN_FAILED
CTRL-EVENT-SCAN-STARTED
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
Removed BSSID f4:ca:e5:e6:01:a0 from ignore list (clear)
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-STARTED
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-STARTED
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-NETWORK-NOT-FOUND
CTRL-EVENT-SCAN-RESULTS
WPS-AP-AVAILABLE
CTRL-EVENT-SSID-REENABLED id=2 ssid="Pretty Fly for A WI-FI"
Added BSSID f4:ca:e5:e6:01:a0 into ignore list, ignoring for 10 seconds
SME: Trying to authenticate with f4:ca:e5:e6:01:a0 (SSID='Pretty Fly for A WI-FI' freq=2462 MHz)
Trying to associate with f4:ca:e5:e6:01:a0 (SSID='Pretty Fly for A WI-FI' freq=2462 MHz)
Associated with f4:ca:e5:e6:01:a0
CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
WPA: Key negotiation completed with f4:ca:e5:e6:01:a0 [PTK=CCMP GTK=CCMP]
Removed BSSID f4:ca:e5:e6:01:a0 from ignore list
CTRL-EVENT-CONNECTED - Connection to f4:ca:e5:e6:01:a0 completed [id=2 id_str=]

It's a short one, because it sometimes takes more than 30 minutes to reconnect... Does anyone have an idea ?

Thanks for taking the time and having a look, I recently ELevated (AlmaLinux project ELevate) 3 servers from AlmaLinux 8 to AlmaLinux 9 (2 years back these same servers were Elevated from CentOS 7 to AlmaLinux 8). The upgrade workt flawlessly and after the upgrade I just had to reinstall 1 package, Zabbix-Agent2. I could access the services running on those servers, websites were perfectly accessable, via SSH I could access the system with no issues. even the ansibleuser could be used for a keypair ssh authentication with no trouble. But when I use ansible to run a playbook on these servers that worked Always in the past and still work on all our other Ubuntu and AlmaLinux Machines, I get the following errors on the 3 machines in question:

[ /etc/ansible ]$ ansible-playbook playbooks/update-linux.yml -C -l ClamAV -vvv
ansible-playbook [core 2.14.14]
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/ansibleuser/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.9/site-packages/ansible
  ansible collection location = /home/ansibleuser/.ansible/collections:/usr/share/ansible/collections
  executable location = /usr/bin/ansible-playbook
  python version = 3.9.18 (main, Aug 23 2024, 00:00:00) [GCC 11.4.1 20231218 (Red Hat 11.4.1-3)] (/usr/bin/python3)
  jinja version = 3.1.2
  libyaml = True
Using /etc/ansible/ansible.cfg as config file
BECOME password: 

Vault password: 
host_list declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
script declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
auto declined parsing /etc/ansible/hosts as it did not pass its verify_file() method
Parsed /etc/ansible/hosts inventory source with yaml plugin
Skipping callback 'default', as we already have a stdout callback.
Skipping callback 'minimal', as we already have a stdout callback.
Skipping callback 'oneline', as we already have a stdout callback.

PLAYBOOK: update-linux.yml *******************************************************************************************************************************
2 plays in playbooks/update-linux.yml

PLAY [landauer] ******************************************************************************************************************************************

TASK [Gathering Facts] ***********************************************************************************************************************************
task path: /etc/ansible/playbooks/update-linux.yml:2
 ESTABLISH SSH CONNECTION FOR USER: ansibleuser
 SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' 10.1.1.22 '/bin/sh -c '"'"'echo ~ansibleuser && sleep 0'"'"''
 (0, b'/home/ansibleuser\n', b'')
 ESTABLISH SSH CONNECTION FOR USER: ansibleuser
 SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' 10.1.1.22 '/bin/sh -c '"'"'( umask 77 && mkdir -p " echo /home/ansibleuser/.ansible/tmp "&& mkdir " echo /home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462 " && echo ansible-tmp-1728362452.3175566-4768-111779545868462=" echo /home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462 " ) && sleep 0'"'"''
 (0, b'ansible-tmp-1728362452.3175566-4768-111779545868462=/home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462\n', b'')
 Attempting python interpreter discovery
 ESTABLISH SSH CONNECTION FOR USER: ansibleuser
 SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' 10.1.1.22 '/bin/sh -c '"'"'echo PLATFORM; uname; echo FOUND; command -v '"'"'"'"'"'"'"'"'python3.11'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.10'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.9'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.8'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.7'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.6'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python3.5'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'/usr/bin/python3'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'/usr/libexec/platform-python'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python2.7'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'/usr/bin/python'"'"'"'"'"'"'"'"'; command -v '"'"'"'"'"'"'"'"'python'"'"'"'"'"'"'"'"'; echo ENDFOUND && sleep 0'"'"''
 (0, b'PLATFORM\nLinux\nFOUND\n/usr/bin/python3.9\n/usr/bin/python3\n/usr/libexec/platform-python\n/usr/bin/python\n/usr/bin/python\nENDFOUND\n', b'')
 ESTABLISH SSH CONNECTION FOR USER: ansibleuser
 SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' 10.1.1.22 '/bin/sh -c '"'"'/usr/bin/python3.9 && sleep 0'"'"''
 (0, b'{"platform_dist_result": [], "osrelease_content": "NAME=\\"AlmaLinux\\"\\nVERSION=\\"9.4 (Seafoam Ocelot)\\"\\nID=\\"almalinux\\"\\nID_LIKE=\\"rhel centos fedora\\"\\nVERSION_ID=\\"9.4\\"\\nPLATFORM_ID=\\"platform:el9\\"\\nPRETTY_NAME=\\"AlmaLinux 9.4 (Seafoam Ocelot)\\"\\nANSI_COLOR=\\"0;34\\"\\nLOGO=\\"fedora-logo-icon\\"\\nCPE_NAME=\\"cpe:/o:almalinux:almalinux:9::baseos\\"\\nHOME_URL=\\"https://almalinux.org/\\ "\\nDOCUMENTATION_URL=\\"https://wiki.almalinux.org/\\ "\\nBUG_REPORT_URL=\\"https://bugs.almalinux.org/\\ "\\n\\nALMALINUX_MANTISBT_PROJECT=\\"AlmaLinux-9\\"\\nALMALINUX_MANTISBT_PROJECT_VERSION=\\"9.4\\"\\nREDHAT_SUPPORT_PRODUCT=\\"AlmaLinux\\"\\nREDHAT_SUPPORT_PRODUCT_VERSION=\\"9.4\\"\\nSUPPORT_END=2032-06-01\\n"}\n', b'')
Using module file /usr/lib/python3.9/site-packages/ansible/modules/setup.py
 PUT /home/ansibleuser/.ansible/tmp/ansible-local-47643ehs1jje/tmprhb1042q TO /home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462/AnsiballZ_setup.py
 SSH: EXEC scp -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' /home/ansibleuser/.ansible/tmp/ansible-local-47643ehs1jje/tmprhb1042q '[10.1.1.22]:/home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462/AnsiballZ_setup.py'
 ESTABLISH SSH CONNECTION FOR USER: ansibleuser
 SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o 'User="ansibleuser"' -o ConnectTimeout=5 -o 'ControlPath="/home/ansibleuser/.ansible/cp/267bb41463"' 10.1.1.22 '/bin/sh -c '"'"'rm -f -r /home/ansibleuser/.ansible/tmp/ansible-tmp-1728362452.3175566-4768-111779545868462/ > /dev/null 2>&1 && sleep 0'"'"''
 (0, b'', b'')
fatal: [ClamAV]: UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via scp: Connection closed\r\n",
    "unreachable": true
}

In the Example I used the ClamAV server, but on 2 other servers I have the same issue. The Other AlmaLinux machines in our setup and installed from scratch with AlmaLinux9 and the playbook works fine. I Also noticed when running DNF it gives me 1 warning: warning: Signature not supported. Hash algorithm SHA1 not available. I already found an article about this on redHat explaining that with the command: "update-crypto-policies --set FUTURE" I could set the server to the newer SHA256/512 crypto policy. But then I loose ALL possible communications to that server except HTTP(s) and fysical console (via vCenter). I think it must be something related to this, Or I need to regenerate something. But is there someone who already found a solution/thread to help me solve the issue? I have 2 more servers to do that are a bit more company critical, so don't want these to suffer too long with this issue. Thanks a lot already for any help.

I have a Debian Linux server and two wireless networks, A and B. Network A is the preferred, faster network. B serves as backup. Therefore I have set both to connect automatically in NetworkManager using nmcli (connection.autoconnect: yes) and given network A a higher priority (connection.autoconnect-priority). It mostly works fine. When I power up the server and both networks are available, it will automatically connect to network A. A problem arises due to specific conditions at this location. We have daily, short power cuts. The server is hooked to an UPS (Uninterruptible Power Supply) so it survives power cuts. Network B is powered by an UPS as well. Network A is not so it goes down when there is a power cut. The server then automatically connects to network B. The power is then restored and network A goes back up. However the server does not seem to care and stays connected to network B until I log in and manually switch it to network A, which would then stay valid until the next power cut. How do I make it so that the OS would detect the favorite network becoming available and automatically reconnect to it?

- How to check if a port is blocked with socat? - How to check with IPv6? I heard a saying that machines behind NAT can still be directly connected via IPv6, is that true? Anyway, say I have a machine behind very complicated setup, and I want to verify if a certain port can be reached, by either IPv4 or IPv6, how to do that with socat? Basically I need to start socat on the machine to listen, then try to conect to it via socat from other machines. I've read https://copyconstruct.medium.com/socat-29453e9fc8a6 , and found it a bit complicated, but I cannot just use netcat because my netcat version does not support IPv6, as per https://unix.stackexchange.com/questions/457670/netcat-how-to-listen-on-a-tcp-port-using-ipv6-address .

I am using and giving a try in Csi Linux distro. She has TorVPN that, at least in theory, routes all the traffic through Tor Network. After service tor status commando I see the service is up. I tried several things, then I'll summarize. I modified a little DNS configurations as a clue of AI. Gone far from the target. Nevertheless, the connection is normal as not using TorVPN. Resuming, it has internet if TorVPN is out the game.

When I try to connect to wifi, dhcpcd gets stuck,

# dhcpcd wlxf42853190543
dhcpcd-10.0.6 starting
DUID 00:01:00:01:2d:1b:d8:8a:f4:e8:53:d9:78:b1
wlxf42853190543: waiting for carrier

and times out. I cannot connect.

I've been upgrading an a bit older HP Pavillion laptop with SSD, more RAM and since I had one lying around, an Intel AX210 m2 wifi adapter. The stock adapter was a single-channel Broadcom BCM943142YHN_2 and to my surprise it had only a single antenna connected, to its right connecter (seen from the m2 connector side). After staring hard at the labels near the connectors I concluded that I'd have to connect that antenna to the Intel's left connector (a quick search on which port is which on each adapter turned up empty - or rather, floaded with irrelevancy). I flipped the laptop, turned it on without closing it (countless plastic tabs and 24 screws!), booted into Linux and LO AND BEHOLD I had dual channel wifi. In Win10 too, after installing the appropriate drivers. This confirmed what I had been told when I ordered the AX210 for another laptop which does have 2 antennas but also only a single-channel adapter: these are just wires and should work with both frequency ranges. In fact, in that system one of the antennas seems rather to be for bluetooth - I have no need for that so as far as I'm concerned I also don't need an antenna for it. I think 5Ghz connectivity continued to work until yesterday evening, but this morning it's gone after a reboot. Laptop hasn't been moved and the antenna connected with a very definite snap so I doubt it can have come lose or develop a bad contact overnight. To me it doesn't really make sense. The 5Ghz signal is strong enough at this location to pick up and it is when I plug in the external RTL-based dongle I'd hoped to eliminate, or by my phone. **Any ideas what could explain why it no longer works, or why it worked yesterday?** Is it possible that the HP BIOS (InsydeH20 v F81) has detected that I put in an "unsupported" wifi module and cut off 5Ghz access (it's still visible in the properties tab of Win10's device manager)? Annoyingly HP disabled the "advanced" BIOS settings, for "security reasons", so I cannot for instance disable the bluetooth function at the lowest level as I'd prefer. **Also, does anyone have pointers for finding out which antenna connector is which on both adapters?**

I'm trying to connect to the internet on my Debian 12 laptop using my phone connection through an USB-C cable. When the cable is connected and the connection sharing is activated on the phone, the Ethernet symbol shows up on the top bar of the desktop (Gnome 43.6). However, I cannot connect to any website from the laptop, although it's accessible from my phone. I tried to shut down and boot again with the cable unplugged, and now the Ethernet symbol shows up directly when booting. I still cannot connect when plugging the cable in again. I also can't connect through my phone's Wifi hotspot with the cable unplugged. Both Ethernet and Wifi have been regularly working between these two devices until now. I suspect Debian is stuck on some kind of old connection it cannot get rid of. What should I do?

I have a window laptop where i have installed 2 ubuntu VM's on VMWARE workstation 17 player. I have downloaded apache on one Virtual machine and DNS on the other. I have a website on ubuntu having apache. I want to connect the two virtual machines so i can access the website from the other virtual machine having DNS.

Running Ubuntu 16.04, I can connect to other websites fine: ping google.com PING google.com (172.217.25.206) 56(84) bytes of data. 64 bytes from nrt12s13-in-f14.1e100.net (172.217.25.206): icmp_seq=1 ttl=54 time=42.6 ms ping yahoo.com PING yahoo.com (98.137.246.7) 56(84) bytes of data. 64 bytes from media-router-fp1.prod1.media.vip.gq1.yahoo.com (98.137.246.7): icmp_seq=1 ttl=49 time=252 ms But I can't ping Github or access it in my browser: ping github.com PING github.com (192.30.255.112) 56(84) bytes of data. From 192.168.0.60 icmp_seq=1 Destination Host Unreachable However, from another PC on the same network everything works fine: ping github.com PING github.com (192.30.255.112) 56(84) bytes of data. 64 bytes from lb-192-30-255-112-sea.github.com (192.30.255.112): icmp_seq=1 ttl=48 time=141 ms What's going on here? I have a feeling it's something to do with Github's IP address's first octet being the same as the local one: 192.xxx.xxx.xxx. EDIT: Output of sudo route -n: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.179.1 0.0.0.0 UG 600 0 0 wlp3s0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 enp0s31f6 172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0 192.0.0.0 0.0.0.0 255.0.0.0 U 100 0 0 enp0s31f6 192.168.179.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp3s0

Problem is exactly as reported in - https://unix.stackexchange.com/questions/237158/ - https://unix.stackexchange.com/questions/331641/ But it is ***not*** the "ssh_exchange_identification:" error, i.e., it's different than the https://unix.stackexchange.com/questions/19378/ one. I'm getting it while doing ssh -T:

$ ssh -T git@github.com
Connection to github.com closed by remote host.

The following message is generated when using ssh -vvv

debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 32000 rmax 35000
debug3: send packet: type 1
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
  #0 client-session (t4 r43 i0/0 o0/0 fd 5/6 cc -1)
Connection to github.com closed by remote host.

I've put the the full log (and diff with normal) to: https://www.diffchecker.com/LF2ZEb8j For ssh -vvT git@github.com, I've put the the log diff to: https://www.diffchecker.com/WjmA7P0c from which there isn't much revealing. Once again, the above problem is from (connecting from) my remote server, of version 1:7.6p1-4ubuntu0.7, which has been working for years, but have now broken for a few weeks. Testing/connecting from my home machine (ver: 1:8.4p1-5) always OK. Comments? Is it that my openssh-client 1:7.6p1-4ubuntu0.7 is too old for github.com? $ apt-cache policy openssh-client openssh-client: Installed: 1:7.6p1-4ubuntu0.7 Candidate: 1:7.6p1-4ubuntu0.7 Version table: *** 1:7.6p1-4ubuntu0.7 500 500 http://azure.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages 100 /var/lib/dpkg/status 1:7.6p1-4ubuntu0.5 500 500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages 1:7.6p1-4 500 500 http://azure.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

I'm using systemd-timer to periodically run a script which consumes a webservice. Problem is, upon system resume or wake-up, internet connectivity would not get started right away but the timer gets fired and hence the script returns error (If the service waits for a couple of seconds, the script would run correctly and there would be no need to postpone the task until next run.) 1- How can I make it so that the timer (or the service associated with it), waits until net connectivity is available? 2- How can I make the timer (or service) not call the script when system is not online yet?

My ubuntu system no longer connects to the internet, I suspect due to lack of updates since I haven't used it for almost two years. However, I now need to use it with internet again, but it fails to connect to both wired and wireless networks (these have changed at home since I last used it due to an upgrade to glass fiber connection, I've tried to connect both at home and at work without success). It might be noteworthy that the Ubuntu system is on the second partition of a laptop that is fully capable of connecting to the internet (both wired and wireless) when I run its Windows partition, so I don't think it's failure to connect has anything to do with the hardware. I am aware that there is something called apt-offline, but the tutorials for this seem to require having access to a machine that is also running some kind of Linux OS and that is connected to the internet. I don't have access to that, but I do have access to multiple Windows 10 machines that have internet access and USB data carriers. I'm struggling to get the files I need on a USB stick due to the Linux terminology whilst using a Windows system. Can someone explain in beginner friendly terms how to update my Ubuntu system using one of my Windows machines? Thank you so much for your time.

I am trying to deploy a web app in a VM, but if I use a NAT adapter, that VM is assigned a private IP. I want to use the bridge adapter to give the VM a real IP in my DHCP network. Both host OS and guest OS are ubuntu 20.04 LTS and when I start the VM with the bridge adapter I only get a message saying: Connection Failed Activation of network connection failed I've searched for a solution for a while now but I can't seem to find one. My current config of the network adapter is: How can I get my VM to have an internet connection with the bridge adapter?

I freshly set up a headless Raspberry Pi on Raspbian. It is connected to the router via ethernet, I tried wifi before with the same issues. I can SSH via ethernet and wifi, I can ping the Pi, from the Pi I can ping the router and other network devices, but I can't ping external IPs. **ifconfig:**

eth0: flags=4163  mtu 1500
        inet 192.168.0.22  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 [ipv6 address]  prefixlen 64  scopeid 0x20
        ether [MAC address]  txqueuelen 1000  (Ethernet)
        RX packets 477  bytes 39836 (38.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 450  bytes 59686 (58.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 12  bytes 1722 (1.6 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 12  bytes 1722 (1.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlan0: flags=4163  mtu 1500
        inet6 [ipv6 address]  prefixlen 64  scopeid 0x20
        ether [MAC address]  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 160  bytes 28019 (27.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

**Routing table:**

route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    202    0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     202    0        0 eth0

**Pings:**

ping 192.168.0.1
PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
64 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=9.69 ms
64 bytes from 192.168.0.1: icmp_seq=2 ttl=64 time=1.48 ms
64 bytes from 192.168.0.1: icmp_seq=3 ttl=64 time=1.80 ms
64 bytes from 192.168.0.1: icmp_seq=4 ttl=64 time=2.12 ms
^C
--- 192.168.0.1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 1.479/3.774/9.694/3.425 ms

ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
^C
--- 8.8.8.8 ping statistics ---
5 packets transmitted, 0 received, 100% packet loss, time 4077ms

How do I diagnose the issue? And how do I resolve it? Please help edit: **traceroute:**

traceroute to 8.8.8.8 (8.8.8.8), 64 hops max
  1   *  *  *
  2   *  *  *
[...]
 58   *  *  *
 59   *  *  192.168.0.22  62.435ms !H

edit2: Removed static IP config, now traceroute outputs:

traceroute to 8.8.8.8 (8.8.8.8), 64 hops max
  1   192.168.0.1  6.217ms  1.847ms  1.332ms
  2   *  *  *
[...]

edit3: tcpdump:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
09:28:06.646658 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 3961577292:3961577484, ack 1645861291, win 501, length 192
09:28:06.648416 IP 192.168.0.22.47393 > [ipv4 - ISP cache #1].domain: 15925+ PTR? a.e.8.1.6.3.b.0.b.b.3.5.0.a.f.9.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:06.688171 IP6 [ipv6 #2].49591 > [ipv6 #1].ssh: Flags [.], ack 192, win 1025, length 0
09:28:08.046962 IP 192.168.0.22.55981 > [ipv4 - ISP cache #2].domain: 46272+ A? 2.debian.pool.ntp.org. (39)
09:28:08.047044 IP 192.168.0.22.55981 > [ipv4 - ISP cache #2].domain: 10446+ AAAA? 2.debian.pool.ntp.org. (39)
09:28:09.761724 IP 192.168.0.12.41326 > 239.255.255.250.1900: UDP, length 125
09:28:10.063180 IP 192.168.0.12.41326 > 239.255.255.250.1900: UDP, length 125
09:28:10.369344 IP 192.168.0.12.41326 > 239.255.255.250.1900: UDP, length 125
09:28:11.653845 IP 192.168.0.22.51128 > [ipv4 - ISP cache #2].domain: 15925+ PTR? a.e.8.1.6.3.b.0.b.b.3.5.0.a.f.9.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:13.052252 IP 192.168.0.22.49091 > [ipv4 - ISP cache #1].domain: 46272+ A? 2.debian.pool.ntp.org. (39)
09:28:13.052340 IP 192.168.0.22.49091 > [ipv4 - ISP cache #1].domain: 10446+ AAAA? 2.debian.pool.ntp.org. (39)
09:28:16.659113 IP 192.168.0.22.47393 > [ipv4 - ISP cache #1].domain: 15925+ PTR? a.e.8.1.6.3.b.0.b.b.3.5.0.a.f.9.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:16.709645 ARP, Request who-has 192.168.0.1 tell 192.168.0.22, length 28
09:28:16.710585 ARP, Reply 192.168.0.1 is-at [MAC #1] (oui Unknown), length 46
09:28:17.055977 ARP, Request who-has 192.168.0.1 tell 192.168.0.15, length 46
09:28:18.057531 IP 192.168.0.22.55981 > [ipv4 - ISP cache #2].domain: 46272+ A? 2.debian.pool.ntp.org. (39)
09:28:18.057633 IP 192.168.0.22.55981 > [ipv4 - ISP cache #2].domain: 10446+ AAAA? 2.debian.pool.ntp.org. (39)
09:28:18.933210 IP 192.168.0.14.57621 > 192.168.0.255.57621: UDP, length 44
09:28:19.800035 IP 192.168.0.12.41552 > 239.255.255.250.1900: UDP, length 125
09:28:20.101830 IP 192.168.0.12.41552 > 239.255.255.250.1900: UDP, length 125
09:28:20.402483 IP 192.168.0.12.41552 > 239.255.255.250.1900: UDP, length 125
09:28:21.664304 IP 192.168.0.22.51128 > [ipv4 - ISP cache #2].domain: 15925+ PTR? a.e.8.1.6.3.b.0.b.b.3.5.0.a.f.9.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:23.064568 IP 192.168.0.22.60984 > [ipv4 - ISP cache #1].domain: 31504+ A? 3.debian.pool.ntp.org. (39)
09:28:23.064668 IP 192.168.0.22.60984 > [ipv4 - ISP cache #1].domain: 20237+ AAAA? 3.debian.pool.ntp.org. (39)
09:28:26.670244 IP 192.168.0.22.42431 > [ipv4 - ISP cache #1].domain: 42575+ PTR? 9.1.8.c.b.f.7.b.e.1.4.0.9.3.8.b.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:28.070047 IP 192.168.0.22.56262 > [ipv4 - ISP cache #2].domain: 31504+ A? 3.debian.pool.ntp.org. (39)
09:28:28.070195 IP 192.168.0.22.56262 > [ipv4 - ISP cache #2].domain: 20237+ AAAA? 3.debian.pool.ntp.org. (39)
09:28:28.745503 ARP, Request who-has 192.168.0.1 tell 192.168.0.12, length 46
09:28:29.830486 IP 192.168.0.12.43134 > 239.255.255.250.1900: UDP, length 125
09:28:30.130431 IP 192.168.0.12.43134 > 239.255.255.250.1900: UDP, length 125
09:28:30.431008 IP 192.168.0.12.43134 > 239.255.255.250.1900: UDP, length 125
09:28:31.675608 IP 192.168.0.22.57569 > [ipv4 - ISP cache #2].domain: 42575+ PTR? 9.1.8.c.b.f.7.b.e.1.4.0.9.3.8.b.0.0.0.0.0.0.0.0.0.0.0.0.0.8.e.f.ip6.arpa. (90)
09:28:46.692132 IP 192.168.0.22.35774 > [ipv4 - ISP cache #1].domain: 36300+ PTR? 22.0.168.192.in-addr.arpa. (43)
09:29:26.736011 IP 192.168.0.22.60246 > [ipv4 - ISP cache #1].domain: 52343+ PTR? 100.8.168.194.in-addr.arpa. (44)
09:29:26.736108 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 368:560, ack 1, win 501, length 192
09:29:46.758046 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 560:688, ack 1, win 501, length 128
09:29:46.758171 IP 192.168.0.22.48623 > [ipv4 - ISP cache #1].domain: 25524+ PTR? 12.0.168.192.in-addr.arpa. (43)
09:30:26.801306 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 688:816, ack 1, win 501, length 128
09:30:26.801792 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 816:912, ack 1, win 501, length 96
09:30:26.802104 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 912:992, ack 1, win 501, length 80
09:30:26.802210 IP 192.168.0.22.49293 > [ipv4 - ISP cache #1].domain: 32774+ PTR? 1.0.168.192.in-addr.arpa. (42)
09:30:26.802431 IP6 [ipv6 #2].49591 > [ipv6 #1].ssh: Flags [.], ack 912, win 1028, length 0
09:30:26.847413 IP6 [ipv6 #2].49591 > [ipv6 #1].ssh: Flags [.], ack 992, win 1028, length 0
09:30:28.207666 IP 192.168.0.22.38721 > [ipv4 - ISP cache #2].domain: 53173+ A? 1.debian.pool.ntp.org. (39)
09:30:46.824371 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 992:1088, ack 1, win 501, length 96
09:30:46.824457 IP 192.168.0.22.60784 > [ipv4 - ISP cache #1].domain: 6213+ PTR? 15.0.168.192.in-addr.arpa. (43)
09:31:06.846322 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1200:1280, ack 1, win 501, length 80
09:31:06.846468 IP 192.168.0.22.53135 > [ipv4 - ISP cache #1].domain: 6352+ PTR? 14.0.168.192.in-addr.arpa. (43)
09:31:06.846724 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1280:1344, ack 1, win 501, length 64
09:31:46.890222 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1344:1440, ack 1, win 501, length 96
09:31:46.890569 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1440:1520, ack 1, win 501, length 80
09:31:46.890892 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1520:1616, ack 1, win 501, length 96
09:31:46.891137 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1616:1680, ack 1, win 501, length 64
09:31:46.891634 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1680:1808, ack 1, win 501, length 128
09:31:46.891903 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1808:1872, ack 1, win 501, length 64
09:31:46.892177 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1872:1936, ack 1, win 501, length 64
09:31:46.892439 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 1936:2016, ack 1, win 501, length 80
09:31:46.892682 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 2016:2080, ack 1, win 501, length 64
09:31:46.893007 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 2080:2192, ack 1, win 501, length 112
09:31:46.901902 IP6 [ipv6 #2].49591 > [ipv6 #1].ssh: Flags [.], ack 2192, win 1029, length 0
09:31:46.902110 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [.], seq 2192:3632, ack 1, win 501, length 1440
09:31:46.902152 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 3632:3904, ack 1, win 501, length 272
09:31:46.902707 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 3904:4000, ack 1, win 501, length 96
09:31:46.902794 IP6 [ipv6 #2].49591 > [ipv6 #1].ssh: Flags [.], ack 3904, win 1029, length 0
09:31:46.902979 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 4000:4080, ack 1, win 501, length 80
09:31:46.903372 IP6 [ipv6 #1].ssh > [ipv6 #2].49591: Flags [P.], seq 4080:4144, ack 1, win 501, length 64

My client installed several AWS instances, all in the same region/datacenter. My task is to install a Redis and a Postgresql instance on one of the machines and make the data store/database accessible from another box. The database server has LAN IP 172.26.14.232 and the server running the db client has IP 172.26.0.215. Postgres is up and running on the database server, checked this using netstat: [ubuntu@ip-172-26-14-232 DATABA ~]$ sudo netstat -tulpn | grep postgre tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN 4539/postgres When I try to connect client box, I get a "connection refused", as if there would be a firewall blocking the access, netcat confirms this: [ubuntu@ip-172-26-0-215 GATE01 ~]$ sudo psql "sslmode=require" --host 172.26.14.232 --user=postgres --password Password for user postgres: psql: could not connect to server: Connection refused Is the server running on host "172.26.14.232" and accepting TCP/IP connections on port 5432? [ubuntu@ip-172-26-0-215 GATE01 ~]$ nc -vz 172.26.14.232 5432 nc: connect to 172.26.14.232 port 5432 (tcp) failed: Connection refused As far as I a can see there is just one port to which I can connect using nc: [ubuntu@ip-172-26-0-215 GATE01 ~]$ nc -vz 172.26.14.232 22 Connection to 172.26.14.232 22 port [tcp/ssh] succeeded! My client says he removed all firewall rules, but then I do not understand the result given above. Somewhere I have read that AWS blocks outbound traffic in such networks, but I cannot check this myself since I have no access to the management console. Bonus question ;-) Found the following on this site: > netcat -vzw 15 domain.com 21 > > If successful, you’ll see: > > Connection to domain.com 21 port [tcp/ftp] succeeded! > > If the port connection is blocked or rejected, you’ll see: > > nc: connect to domain port 21 (tcp) failed: Connection refused The author possibly makes a difference between "blocked" and "rejected", whereby I assume that, in the latter case, it is meant that there is a fw rule "DENY" installed for this port, but I have no clue what he means by "blocked". Is there a second technical possibility or does he just use "blocked" and "rejected" synonymously? EDIT: ----- Astonishingly, it is possible to setup a client-server connection using nc (after shutting down the db): [ubuntu@ip-172-26-14-232 DATABA ~]$ nc -l 5432 [ubuntu@ip-172-26-0-215 GATE01 ~]$ nc 172.26.14.232 5432 hello And on 172.26.14.232 we get: hello