Turning off ipv6 on macos 14 worked fine with sudo networksetup -setv6off Wi-Fi. Has anything changed with 15 that this has stopped working? I still see ipv6 traffic even after turning off ipv6 traffic with sudo networksetup -setv6off Wi-Fi

Based on previous research, I created the following two Bash aliases to turn ipv6 off and on:

alias ipv6off="networksetup -setv6off 'USB 10/100/1000 LAN'"
alias ipv6on="networksetup -setv6automatic 'USB 10/100/1000 LAN'"

The question now is how to **get** the current state of my IPv6, whether it's on or off. The manual of networksetup doesn't mention such an option that I found. Is there a trick to get this information from the command line? The context of this is that the VPN provider I use doesn't support IPv6 so I need to turn it off when I use it.

I have working IPv6 interface with /64 prefix. It means I can connect to direct IPv6 addresses through browser but can't connect to IPv6 hosts like testv6.madore.org. The issue is in DNS configuration where I don't have flag "Request AAAA records": $ scutil --dns resolver #1 search domain : xxxxxxxx nameserver : xxxxxxxx nameserver : xxxxxxxx nameserver : xxxxxxxx if_index : 4 (en0) flags : Scoped, Request A records reach : Reachable Can someone tell me how to manually add/enable that flag too look like: flags : Scoped, Request A records, Request AAAA records

Recently there is instability in macOS reliably generating stable 'autoconf secured' IPv6 address upon reboot. Mine is a stateless IPv6 environment. This seems to be correlated with update to 14.4 (23E214). However, I've insufficient logging and timing to really place the blame on the update. Perhaps it's slightly older. Is this a bug in the OS? …a new feature? Has anyone else noticed such behavior; their network interfaces assigning/generating these random addresses? These should be quite stable provided that the local VLAN and network prefix is also stable. I'm not interested in disabling macOS's default use of autoconf temporary addresses in order to land on a static address. I'm not interested in reconfiguring the LAN to a stateful implementation. Here are some relevant kernel settings: user@host:~ $ sysctl -a | grep tempaddr net.inet6.ip6.use_tempaddr: 1 net.inet6.ip6.prefer_tempaddr: 1 net.inet6.ip6.ula_use_tempaddr: 0 …hope someone out there has some thoughts.

Host is a Mac mini X86 running Sonoma 14.2.1, VMware Fusion Player Version 13.5.0 (which are current as of this writing.). Guest vms include Windows 11, macOS Sonoma 14.2.1, and a Linux, where I was best able to isolate and diagnose the problem. Consider this transcript (with some extra blank lines for readability), which starts in Terminal on the host, and continues via ssh on a fresh (File/New/Create custom ...) vm running an installation CD:

scott@Mac-mini-x86 ~ $ scutil --dns |  tail -9
DNS configuration (for scoped queries)

resolver #1
  search domain : attlocal.net
  nameserver : 2600:1700:6b0:e60::1
  nameserver : 192.168.1.254
  if_index : 11 (en1)
  flags    : Scoped, Request A records, Request AAAA records
  reach    : 0x00020002 (Reachable,Directly Reachable Address)


scott@Mac-mini-x86 ~ $ ping -c 1 www.ibm.com
PING user-att-162-198-200-0.e7817.dscx.akamaiedge.net (23.0.23.183): 56 data bytes
64 bytes from 23.0.23.183: icmp_seq=0 ttl=53 time=14.879 ms

--- user-att-162-198-200-0.e7817.dscx.akamaiedge.net ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 14.879/14.879/14.879/0.000 ms


scott@Mac-mini-x86 ~ $ ping6 -c 1 www.ibm.com
PING6(56=40+8+8 bytes) 2600:1700:6b0:e60:b9a0:4f76:4b85:6a1d --> 2600:1407:7400:d87::1e89
16 bytes from 2600:1407:7400:d87::1e89, icmp_seq=0 hlim=50 time=32.135 ms

--- user-att-162-198-200-0.e7817.dscx.akamaiedge.net ping6 statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 32.135/32.135/32.135/0.000 ms


scott@Mac-mini-x86 ~ $ ssh $vm



livecd ~ # ping -c 1 23.0.23.183
PING 23.0.23.183 (23.0.23.183) 56(84) bytes of data.
64 bytes from 23.0.23.183: icmp_seq=1 ttl=53 time=21.6 ms

--- 23.0.23.183 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 21.590/21.590/21.590/0.000 ms


livecd ~ # ping6 -c 1 2600:1407:7400:d87::1e89
PING 2600:1407:7400:d87::1e89(2600:1407:7400:d87::1e89) 56 data bytes

--- 2600:1407:7400:d87::1e89 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms


livecd ~ # ping -c 1 www.ibm.com
PING www.ibm.com(g2600-1407-7400-0d94-0000-0000-0000-1e89.deploy.static.akamaitechnologies.com (2600:1407:7400:d94::1e89)) 56 data bytes

--- www.ibm.com ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms


livecd ~ # cat /etc/resolv.conf 
# Generated by dhcpcd from enp2s1.dhcp, enp2s1.dhcp6, enp2s1.ra
# /etc/resolv.conf.head can replace this line
domain attlocal.net
nameserver 192.168.1.254
nameserver 2600:1700:6b0:e60::1
# /etc/resolv.conf.tail can replace this line

First thing to note is that although this example was run on an installation image in a fresh vm, essentially the same thing happens in a Windows VM or a macOS VM -- ipv6 doesn't work! Back to the story: I ping www.ibm.com, both with ping (ipv4) and ping6 (ipv6) while at the host -- works great, and quickly. In the guest vm, the ping still works, and quickly, but the ping6 just times out. Why did I use explicit addresses on the guest? The last experiment shows that on the guest, www.ibm.com will resolve to an ipv6 address (DNS lookup working, right?) but then can't be reached 🧐. Note also that scutil (on the Mac) or cat /etc/resolv.conf (on the guest) both show that same addresses, ipv4 and ipv6, for dsldevice.attlocal.net, my router. Perhaps there is some configuration magic in the .vmx file or something similar that could make ipv6 just work, or if not, make ipv6 fail in a way that things don't get confused, and just use ipv4 like the Before Times.

I've recently been trying to properly configure IPv6 for everything in my network, however I've run into an issue with using my Pihole resolver from macOS Monterey. Since the public IPv6 prefix may change, I'm distributing its link-local IPv6 address on my local network, which is causing an issue on my Mac. The following demonstrates it clearly:

➜  ~ dig @fe80::fea5:8099:fe4f:8ac6%en0 google.com     
;; reply from unexpected source: fe80:e::fea5:8099:fe4f:8ac6%14#53, expected fe80::fea5:8099:fe4f:8ac6%14#53
^C%    
➜  ~ nslookup google.com fe80::fea5:8099:fe4f:8ac6%en0
;; reply from unexpected source: fe80:e::fea5:8099:fe4f:8ac6%14#53, expected fe80::fea5:8099:fe4f:8ac6%14#53
^C  
➜  ~ nslookup google.com fe80:e::fea5:8099:fe4f:8ac6%en0
Server:		fe80:e::fea5:8099:fe4f:8ac6%en0
Address:	fe80:e::fea5:8099:fe4f:8ac6%14#53

Non-authoritative answer:
Name:	google.com
Address: 142.250.81.238

➜  ~ ping6  fe80::fea5:8099:fe4f:8ac6%en0 
PING6(56=40+8+8 bytes) fe80::1c4c:232:1096:128a%en0 --> fe80::fea5:8099:fe4f:8ac6%en0
16 bytes from fe80::fea5:8099:fe4f:8ac6%en0, icmp_seq=0 hlim=64 time=5.584 ms
16 bytes from fe80::fea5:8099:fe4f:8ac6%en0, icmp_seq=1 hlim=64 time=2.664 ms

➜  ~ ping6  fe80:e::fea5:8099:fe4f:8ac6%en0
PING6(56=40+8+8 bytes) fe80::1c4c:232:1096:128a%en0 --> fe80::fea5:8099:fe4f:8ac6%en0
16 bytes from fe80::fea5:8099:fe4f:8ac6%en0, icmp_seq=0 hlim=64 time=6.354 ms
16 bytes from fe80::fea5:8099:fe4f:8ac6%en0, icmp_seq=1 hlim=64 time=2.965 ms

➜  ~ ifconfig
en0: flags=8863 mtu 1500
	options=6463
	ether bc:d0:74:43:e1:d6 
	inet6 fe80::1c4c:232:1096:128a%en0 prefixlen 64 secured scopeid 0xe 
    [...]

It seems like _something_ inserts an improper subnet id (which always matches the scope id from ifconfig, but changes across reboots) into the address, but can also strip it out - just doesn't do it properly on DNS queries. Running Wireshark on those DNS queries confirms that on the actual network adapter the packets have the proper IPv6 addresses (no subnet id). Therefore I believe this is somewhere within the OS. I read [here](https://stackoverflow.com/a/5891805/2228320) that macOS inserts the subnet id for network adapter identification in the kernel so it'd seem it's not stripped out. That'd lead me to believe it's a bug in the kernel, but it's been unnoticed for many years (IPv6 isn't _that_ new)? Non-macOS machines don't have this issue and resolve these names properly and macOS is also totally fine with resolving with the publicly-routable address as well. Any idea what this could be/how to fix it?

MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports) / macOS Big Sur 11.4 I'm experiencing a weird WiFi issue at our remote office where I'm only able to connect to IPv6 addresses and not IPv4 addresses. Ping does not work, ping6 works. Local DNS works as ping6 resolves correctly. I can access google.com in my browser (resolves to an IPv6) but not stackoverflow.com (resolves to an IPv4). I've tried rebooting both my machine as well as the router. My iPhone works correctly on the network and shows similar values for the network addresses. My mobile hotspot works and other WiFis work on the Macbook. Internet is working for everyone else and everything was working fine in May when I last connected to this network (I did update from Mojave to Big Sur in the meantime but otherwise the set-up should be the same). I've tried switching IPv6 to link-local only, configured IPv4 manually, removed external DNS addresses, disabled all proxies, turned the firewall off, flushed the DNS cache, booted to safe mode, disabled IPv6 completely via Terminal, uninstalled NordVPN, and done other things I don't even remember anymore and I've run out of things to try. I don't have access to configure the router, but aside from that does anybody have any ideas?

iOS and macOS long ago implemented support for the privacy extensions of IPv6 networking, iOS in version 4.3 and macOS in version 10.7. The Apple document IPv6 security says in part that temporary addresses have a lifetime of 24 hours. My question is, how is the expiry time chosen? Is it at multiples of 24 hours after the last boot? Or it is tied to the local timezone (and happens overnight)? Or is it at random, with some jitter from a 24-hour schedule? Or something else?

I see this in Settings, but not the ipv6 address. Tried ifconfig

en0: flags=8863 mtu 1500
	options=6463
	ether a0:78:17:80:b0:63 
	inet6 fe80::872:f16d:4262:fcbe%en0 prefixlen 64 secured scopeid 0xb 
	inet 192.168.0.74 netmask 0xffffff00 broadcast 192.168.0.255
	nd6 options=201
	media: autoselect
	status: active

But I was told, this is not real ipv6 address, but localhost or loopback: fe80::872:f16d:4262:fcbe

For IPv4, MTU can be found with sweep-ping: ping -g 1464 -G 1508 -c 2 -h 1 -D 1.1.1.1 or by manually decreasing ping after a huge ping: ping -c1 -D -s 1472 1.1.1.1 For IPv6, the easiest method I'm aware of is to use ping or something else then check netstat -narWl -f inet6 and find the relevant IP address. (edit: which doesnt even determine that for a path but for an interface only. so the result is strictly an upper bound) Is there a more practical way of determining the MTU of an IPv6 path?

Before I updated to 12.5 I was able to connect via SSH with no problems, but after the update I can no longer connect. The situation is similar to the following https://apple.stackexchange.com/questions/444673/unable-to-ssh-to-other-servers-after-monterey-12-5-upgrade I did some additional checking. I tried connecting from a Parallels virtual machine and was able to connect via SSH from a Linux virtual machine and a Windows virtual machine, but not from macOS (12.3.1) Below is ssh -vvv info It seems to be working fine until the ssh authentication. OpenSSH_8.6p1, LibreSSL 3.3.6 (omitted) debug1: Authentication succeeded (publickey). (omitted) Authenticated to host.name ([ipaddr]:22). debug1: channel 0: new [client-session] debug3: ssh_session2_open: channel_new: 0 debug2: channel 0: send open debug3: send packet: type 90 debug1: Requesting no-more-sessions@openssh.com debug3: send packet: type 80 debug1: Entering interactive session. debug1: pledge: exec debug3: receive packet: type 80 debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0 debug3: client_input_hostkeys: received RSA key SHA256:keyhash debug3: client_input_hostkeys: received ECDSA key SHA256:keyhash debug3: client_input_hostkeys: received ED25519 key SHA256:keyhash debug1: client_input_hostkeys: searching /Users/username/.ssh/known_hosts for hostname / (none) debug3: hostkeys_foreach: reading file "/Users/username/.ssh/known_hosts" debug3: hostkeys_find: found ssh-ed25519 key at /Users/username/.ssh/known_hosts:15 debug3: hostkeys_find: found ssh-rsa key at /Users/username/.ssh/known_hosts:16 debug3: hostkeys_find: found ecdsa-sha2-nistp256 key at /Users/username/.ssh/known_hosts:17 debug1: client_input_hostkeys: searching /Users/username/.ssh/known_hosts2 for hostname / (none) debug1: client_input_hostkeys: hostkeys file /Users/username/.ssh/known_hosts2 does not exist debug3: client_input_hostkeys: 3 server keys: 0 new, 3 retained, 0 incomplete match. 0 to remove debug1: client_input_hostkeys: no new or deprecated keys from server debug3: receive packet: type 91 debug2: channel_input_open_confirmation: channel 0: callback start debug1: X11 forwarding requested but DISPLAY not set debug2: fd 5 setting TCP_NODELAY debug3: set_sock_tos: set socket 5 IP_TOS 0x48 debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug3: send packet: type 98 debug1: Sending environment. debug3: Ignored env __CFBundleIdentifier debug3: Ignored env TMPDIR debug3: Ignored env XPC_FLAGS debug3: Ignored env TERM debug3: Ignored env SSH_AUTH_SOCK debug3: Ignored env XPC_SERVICE_NAME debug3: Ignored env TERM_PROGRAM debug3: Ignored env TERM_PROGRAM_VERSION debug3: Ignored env TERM_SESSION_ID debug3: Ignored env SHELL debug3: Ignored env HOME debug3: Ignored env LOGNAME debug3: Ignored env USER debug3: Ignored env PATH debug3: Ignored env SHLVL debug3: Ignored env PWD debug3: Ignored env OLDPWD debug3: Ignored env HOMEBREW_PREFIX debug3: Ignored env HOMEBREW_CELLAR debug3: Ignored env HOMEBREW_REPOSITORY debug3: Ignored env MANPATH debug3: Ignored env INFOPATH debug3: Ignored env NVM_DIR debug3: Ignored env NVM_CD_FLAGS debug3: Ignored env NVM_BIN debug3: Ignored env NVM_INC debug3: Ignored env JAVA_HOME debug1: channel 0: setting env LANG = "ja_JP.UTF-8" debug2: channel 0: request env confirm 0 debug3: send packet: type 98 debug3: Ignored env _ debug3: Ignored env __CF_USER_TEXT_ENCODING 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 0 rmax 32768 debug3: send packet: type 80 debug3: send packet: type 1 client_loop: send disconnect: Broken pipe Below is the console log 17:28:33.343367+0900 kernel arm64e_plugin_host: running binary "ssh" in keys-off mode due to entitlement: com.apple.private.security.clear-library-validation 17:28:33.349023+0900 opendirectoryd UID: 501, EUID: 501, GID: 20, EGID: 20, PID: 19816, PROC: ssh RPC: getpwuid, Module: SystemCache, rpc_version: 2, uid: 501 17:28:33.351006+0900 opendirectoryd UID: 501, EUID: 501, GID: 20, EGID: 20, PID: 19816, PROC: ssh RPC: getservbyname, Module: SystemCache, proto: , rpc_version: 2, name: 17:28:33.351876+0900 ssh networkd_settings_read_from_file initialized networkd settings by reading plist directly 17:28:33.352116+0900 ssh networkd_settings_read_from_file initialized networkd settings by reading plist directly 17:28:33.352392+0900 ssh nw_connection_create_with_id [C1] create connection to Hostname#1c2b53eb:22 17:28:33.352643+0900 ssh [C1 93F547D1-F80F-40C8-8AFB-54579889F941 Hostname#1c2b53eb:22 tcp, attribution: developer, context: Default Network Context (private), proc: F767ECD7-40C5-38A7-954F-79C7799C1079, allow socket access, prefer no proxy] start 17:28:33.352679+0900 ssh nw_endpoint_handler_start [C1 Hostname#1c2b53eb:22 initial path ((null))] 17:28:33.352708+0900 ssh [C1 Hostname#1c2b53eb:22 initial path ((null))] event: path:start @0.000s 17:28:33.353212+0900 ssh [C1 Hostname#1c2b53eb:22 waiting path (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: path:satisfied @0.000s, uuid: D89C9BA6-3009-42D8-BEDE-E7110ED5C92A 17:28:33.353243+0900 ssh nw_connection_endpoint_report_on_nw_queue [C1 Hostname#1c2b53eb:22 waiting path (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] skipping state update 17:28:33.353308+0900 ssh [C1 Hostname#1c2b53eb:22 in_progress resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: resolver:start_dns @0.000s 17:28:33.353327+0900 ssh nw_connection_report_state_with_handler_on_nw_queue [C1] reporting state preparing 17:28:33.353553+0900 opendirectoryd UID: 501, EUID: 501, GID: 20, EGID: 20, PID: 19816, PROC: ssh RPC: getservbyport, Module: SystemCache, proto: , rpc_version: 2, port: 22 17:28:33.353802+0900 ssh nw_resolver_create_dns_getaddrinfo_locked [C1] Starting host resolution Hostname#1c2b53eb:22, flags 0xc000d000 proto 0 using hostname: 17:28:33.354187+0900 mDNSResponder [R1920] getaddrinfo start -- flags: 0xC000D000, ifindex: 0, protocols: 0, hostname: , options: 0x8 {use-failover}, client pid: 19816 (ssh) 17:28:33.355158+0900 ssh nw_resolver_create_dns_getaddrinfo_locked_block_invoke [C1] Got 2 DNS results 17:28:33.355191+0900 ssh nw_resolver_create_dns_getaddrinfo_locked_block_invoke [C1] Got DNS result type NoAddress ifindex=0 IN6ADDR_ANY 17:28:33.355207+0900 ssh nw_resolver_create_dns_getaddrinfo_locked_block_invoke [C1] Got DNS result type Add ifindex=0 IPv4#fe3a2481 17:28:33.355222+0900 ssh nw_resolver_create_dns_getaddrinfo_locked_block_invoke [C1] Got DNS negative reason: query suppressed 17:28:33.355330+0900 mDNSResponder [R1920] getaddrinfo stop -- hostname: , client pid: 19816 (ssh) 17:28:33.355319+0900 ssh nw_endpoint_resolver_update [C1 Hostname#1c2b53eb:22 in_progress resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] Adding endpoint handler for IPv4#fe3a2481:22 17:28:33.355361+0900 ssh [C1 Hostname#1c2b53eb:22 in_progress resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: resolver:receive_dns @0.002s 17:28:33.355384+0900 ssh nw_resolver_create_dns_getaddrinfo_locked_block_invoke [C1] Invalidating getaddrinfo DNS object 17:28:33.355412+0900 ssh nw_endpoint_resolver_start_next_child [C1 Hostname#1c2b53eb:22 in_progress resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] starting child endpoint IPv4#fe3a2481:22 17:28:33.355428+0900 ssh nw_endpoint_handler_start [C1.1 IPv4#fe3a2481:22 initial path ((null))] 17:28:33.355607+0900 ssh [C1.1 IPv4#fe3a2481:22 initial path ((null))] event: path:start @0.002s 17:28:33.355843+0900 ssh [C1.1 IPv4#fe3a2481:22 waiting path (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: path:satisfied @0.003s, uuid: DD9095F0-4C3F-41CF-B904-3C99A3F32AA3 17:28:33.356190+0900 ssh nw_endpoint_flow_setup_protocols [C1.1 IPv4#fe3a2481:22 in_progress socket-flow (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] setup flow id 1892069E-6306-48B5-B0CB-BF8E83C7301B 17:28:33.356712+0900 ssh [C1.1 IPv4#fe3a2481:22 in_progress socket-flow (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: flow:start_connect @0.004s 17:28:33.357086+0900 ssh nw_endpoint_resolver_start_next_child [C1 Hostname#1c2b53eb:22 in_progress resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] starting next child endpoint in 100ms 17:28:33.405934+0900 ssh nw_socket_handle_socket_event [C1.1:1] Socket received CONNECTED event 17:28:33.406369+0900 ssh nw_flow_connected [C1.1 IPv4#fe3a2481:22 in_progress socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] Output protocol connected (socket) 17:28:33.406693+0900 ssh nw_endpoint_flow_connected_path_change [C1.1 IPv4#fe3a2481:22 ready socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] Connected path is satisfied, viable 17:28:33.406810+0900 ssh [C1.1 IPv4#fe3a2481:22 ready socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] event: flow:finish_connect @0.054s 17:28:33.408118+0900 ssh nw_connection_endpoint_report_on_nw_queue [C1] Connected fallback generation 0 17:28:33.408159+0900 ssh nw_connection_report_state_with_handler_on_nw_queue [C1] reporting state ready 17:28:33.408368+0900 ssh [C1 Hostname#1c2b53eb:22 ready resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: flow:finish_connect @0.055s 17:28:33.408525+0900 ssh [C1.1 IPv4#fe3a2481:22 ready socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] event: flow:changed_viability @0.055s 17:28:33.408571+0900 ssh [C1 Hostname#1c2b53eb:22 ready resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: flow:changed_viability @0.055s 17:29:23.355087+0900 ssh nw_socket_handle_socket_event [C1.1:1] Socket received TIMEOUT event 17:29:23.355113+0900 ssh nw_socket_handle_socket_event [C1.1:1] Socket received DISCONNECTED event 17:29:23.355159+0900 ssh nw_socket_handle_socket_event [C1.1:1] Socket SO_ERROR: 0 17:29:23.358937+0900 opendirectoryd PID: 19816, Client: 'ssh', exited with 0 session(s), 0 node(s) and 0 active request(s) 17:29:23.355396+0900 ssh nw_flow_error [C1.1 IPv4#fe3a2481:22 ready socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] Output protocol (socket) sent error: Operation timed out 17:29:23.355448+0900 ssh nw_flow_disconnected [C1.1 IPv4#fe3a2481:22 ready socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] Output protocol disconnected 17:29:23.355766+0900 ssh [C1.1 IPv4#fe3a2481:22 failed socket-flow (satisfied (Path is satisfied), viable, interface: en0, ipv4, dns, expensive)] event: flow:disconnect @50.003s, error Operation timed out 17:29:23.356370+0900 ssh nw_connection_report_state_with_handler_on_nw_queue [C1] reporting state failed error Operation timed out 17:29:23.356554+0900 ssh [C1 Hostname#1c2b53eb:22 failed resolver (satisfied (Path is satisfied), interface: en0, ipv4, dns, expensive)] event: flow:disconnect @50.004s Then I noticed that I can't get an ssh connection at the office, but I can get an ssh connection from home. I am assuming that this is related to the fact that our office internet connection uses IPv6 native connection using IPoE and the ssh connection destination is an IPv4 IP address.

I would like to check some websites by using IPv6 only: not only connecting with an IPv6 address but also checking that every other following connection (e.g., for embedded content with iframes) is performed with IPv6. Is there a browser where I can disable IPv4? Or a proxy I can install?

Im really just curious to try IPv6 and see what happens. Is it possible to turn on IPv6 and to turn off IPv4 on my Mac? If it is possible, how can I do it?

I recently was setting up IPv6 on my home network and while setting up several nodes noticed that the DHCPv6 server was using these DUID strings to identify clients as it assigned IPv6 IPs to the various hosts. **NOTE:** DUID is the following: > The DHCP unique identifier (DUID) is used by a client to get an IP address from a DHCPv6 server. It has a 2-byte DUID type field, and a variable-length identifier field up to 128 bytes. Its actual length depends on its type. The server compares the DUID with its database and delivers configuration data (address, lease times, DNS servers, etc.) to the client. Where can I find this on the client side via the CLI on MacOS? ### References - [Dynamic Host Configuration Protocol version 6 (DHCPv6) Wikipedia](https://en.wikipedia.org/wiki/DHCPv6)

I need to use a sofware that only supports IPv4 on iOS 15, but my ISP provides IPv6 addresses by default. How do I force my iOS device to use IPv4 only on a certain Wi-Fi network, or the other way around (force IPv6)?

The answer to https://apple.stackexchange.com/questions/125068/is-there-an-equivalent-utility-to-linuxs-tracepath-for-os-x suggests to use

ping -g 1444 -G 1508 -c 2 -h 1 -D example.com

How do I modify this for ipv6? Tried

ping6 -g 1444 -G 1508 -c 2 -h 1 -D 2606:4700:4700::1111

but this gives a ping6: getaddrinfo for the gateway 1444: nodename nor servname provided, or not known error. EDIT: If you wish to determine the MTU of a path then don't forget -m as described here https://njetwork.wordpress.com/2014/01/17/ping6-and-fragments/ and use `netstat -narWl -f inet6 `

My mac machine has been assigned two public ipv6 addresses with same prefix. One is autoconf temporary and the other is autoconf secured. I know about secured one but what is the purpose of autoconf temporary address? Thanks

I have just switched to an Internet provider offering full dual stack IPv4/6 support, using a Fritzbox 7530 and am experiencing a delay , seemingly in name resolution, when using 'ping6'. The same configuration is also supporting iOS, windows, linux - and these devices all seem to work fine. The symptom is: 'ping www.ibm.com' -> instant response, start getting icmp request/response 'ping6 'www.ibm.com' -> About a 3-4s delay after typing the command before the pings start ie:

$ ping6 www.ibm.com                                                                                         
... delay here ...
PING6(56=40+8+8 bytes) 2a02:8010:687f:0:2dbc:1ea2:a301:b111 --> 2a02:26f0:e8:491::b3a
16 bytes from 2a02:26f0:e8:491::b3a, icmp_seq=0 hlim=58 time=11.621 ms
16 bytes from 2a02:26f0:e8:491::b3a, icmp_seq=1 hlim=58 time=10.486 ms
16 bytes from 2a02:26f0:e8:491::b3a, icmp_seq=2 hlim=58 time=11.994 ms

The same behaviour is seen for other IPv6 sites such as ipv6.google.com Using 'nslookup' I also get a delay:

$ nslookup                                                                                                   
... delay actually occurs here
> ipv6.google.com
Server:		192.168.178.1
Address:	192.168.178.1#53

Non-authoritative answer:
ipv6.google.com	canonical name = ipv6.l.google.com.
>

That delay is almost as if it's reverse resolving itself - or a localhost issue? All the ipv6 testers I've tried in a browser suggest my IPv6 config is fine, sites reachable I don't notice delays in google chrome If IPv4 is disabled no delays occur The router is set to automatic IPv6 (with fast commit) The macOS Wifi adapter is set to automatic for ipv6 (and dhcp for ipv4) scutil --dns ends with

DNS configuration (for scoped queries)

resolver #1
  search domain : fritz.box
  nameserver : 192.168.178.1
  nameserver : fd00::2e91:abff:fe55:2d26
  if_index : 5 (en0)
  flags    : Scoped, Request A records, Request AAAA records
  reach    : 0x00020002 (Reachable,Directly Reachable Address)

So ipv6 addresses are being requested /etc/hosts has

##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1 localhost
::1 localhost
fe80::1%lo0 localhost
# End of section
192.168.178.48 pi4

Any ideas why the delay? Once past that ipv6 and ipv4 are both working fine it seems (from limited tests so far)

If I understood correctly, when a device connects to a network (wireless in my case), it will send both a DHCPv4 and DHCPv6 (if supported). I've setup openwrt on my router in order to view the DHCP requests (with wireshark). I have that windows clients consistently send both DHCP and DHCPv6 requests, but it looks like iPhones (iOS 14) never do. (DHCPv6 is not supported on Android, it seems) Now, my router doesn't have a DHCPv6 sever, but I assumed it doesn't matter because I'm not interested in the station actually acquiring an address, I just want to see the request. How does an iOS device decide whether to send a DHCPv6 request, and how can I force it to do so? Does the iOS device somehow know that there's no DHCPv6 server before sending a request?

My ISP provides me only with an IPv4 address. After setting up a connection to my university OpenVPN server, I get an IPv6 address. With an example IPv6 address www6.fit.vutbr.cz I can: * host www6.fit.vutbr.cz * ping6 www6.fit.vutbr.cz * traceroute6 www6.fit.vutbr.cz * open http://[2001:67c:1220:809::93e5:916] in a web browser (safari/firefox) BUT, I cannot: * open www6.fit.vutbr.cz in a web browser i.e. web browser does not resolve an ipv6 dns address. If I add the following mapping to /etc/hosts 2001:67c:1220:809::93e5:916 www6.fit.vutbr.cz the web browser finally works. I think it has something to do with scutil --dns showing: DNS configuration resolver #1 search domain : lan nameserver : 192.168.1.1 nameserver : 8.8.8.8 nameserver : 8.8.4.4 flags : Request A records reach : 0x00020002 (Reachable,Directly Reachable Address) I believe, I should see Request AAAA records. Why does host and traceroute6 and ping6 resolve the DNS, but the web browsers don't? Any suggestions? Thanks