Sample Header Ad - 728x90

How to setup an ssh tunnel "-w flag" between macos and linux

2 votes
1 answer
58 views
When trying to open a tunnel using ssh -w between a local(Macos) and a remote (Linux server), it fails due to the fact that Macos doesn't support the classic tun interfaces that ssh can use which results in the error below:
root@macos ~ $ ssh -w any:any root@linux-server

Tunnel device open failed.
Could not request tunnel forwarding.
but Macos does support "Utun" interfaces and are used in numerous vpn clients like wireguard and fortigate, can these be used with ssh? how can i use the utun APIs in Macos with ssh to make it work? **UPDATE** output of sudo ssh -vvvw any:any root@server:
OpenSSH_9.9p2, LibreSSL 3.3.6
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: include /etc/ssh/ssh_config.d/* matched no files
debug1: /etc/ssh/ssh_config line 54: Applying options for *
debug2: resolve_canonicalize: hostname 1.1.1.1 is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/var/root/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/var/root/.ssh/known_hosts2'
debug1: Authenticator provider $SSH_SK_PROVIDER did not resolve; disabling
debug3: channel_clear_timeouts: clearing
debug3: ssh_connect_direct: entering
debug1: Connecting to 1.1.1.1 [1.1.1.1] port 22.
debug3: set_sock_tos: set socket 3 IP_TOS 0x48
debug1: Connection established.
debug1: identity file /var/root/.ssh/id_rsa type -1
debug1: identity file /var/root/.ssh/id_rsa-cert type -1
debug1: identity file /var/root/.ssh/id_ecdsa type -1
debug1: identity file /var/root/.ssh/id_ecdsa-cert type -1
debug1: identity file /var/root/.ssh/id_ecdsa_sk type -1
debug1: identity file /var/root/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /var/root/.ssh/id_ed25519 type -1
debug1: identity file /var/root/.ssh/id_ed25519-cert type -1
debug1: identity file /var/root/.ssh/id_ed25519_sk type -1
debug1: identity file /var/root/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /var/root/.ssh/id_xmss type -1
debug1: identity file /var/root/.ssh/id_xmss-cert type -1
debug1: identity file /var/root/.ssh/id_dsa type -1
debug1: identity file /var/root/.ssh/id_dsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_9.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_9.6p1 Ubuntu-3ubuntu13.12
debug1: compat_banner: match: OpenSSH_9.6p1 Ubuntu-3ubuntu13.12 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 1.1.1.1:22 as 'root'
debug3: record_hostkey: found key type ED25519 in file /var/root/.ssh/known_hosts:1
debug3: record_hostkey: found key type RSA in file /var/root/.ssh/known_hosts:2
debug3: record_hostkey: found key type ECDSA in file /var/root/.ssh/known_hosts:3
debug3: load_hostkeys_file: loaded 3 keys from 1.1.1.1
debug1: load_hostkeys: fopen /var/root/.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug3: order_hostkeyalgs: have matching best-preference key type ssh-ed25519-cert-v01@openssh.com, using HostkeyAlgorithms verbatim
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,mlkem768x25519-sha256,curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c,kex-strict-c-v00@openssh.com
debug2: host key algorithms: ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ssh-ed25519@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-s,kex-strict-s-v00@openssh.com
debug2: host key algorithms: rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug3: kex_choose_conf: will use strict KEX ordering
debug1: kex: algorithm: sntrup761x25519-sha512@openssh.com
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC:  compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC:  compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ssh-ed25519 SHA256:somekey
debug3: record_hostkey: found key type ED25519 in file /var/root/.ssh/known_hosts:1
debug3: record_hostkey: found key type RSA in file /var/root/.ssh/known_hosts:2
debug3: record_hostkey: found key type ECDSA in file /var/root/.ssh/known_hosts:3
debug3: load_hostkeys_file: loaded 3 keys from 1.1.1.1
debug1: load_hostkeys: fopen /var/root/.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug1: Host '1.1.1.1' is known and matches the ED25519 host key.
debug1: Found key in /var/root/.ssh/known_hosts:1
debug3: send packet: type 21
debug1: ssh_packet_send2_wrapped: resetting send seqnr 3
debug2: ssh_set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: Sending SSH2_MSG_EXT_INFO
debug3: send packet: type 7
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: ssh_packet_read_poll2: resetting read seqnr 3
debug1: SSH2_MSG_NEWKEYS received
debug2: ssh_set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug2: KEX algorithms: sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,mlkem768x25519-sha256,curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c,kex-strict-c-v00@openssh.com
debug2: host key algorithms: ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ssh-ed25519@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug3: kex_input_ext_info: extension server-sig-algs
debug1: kex_ext_info_client_parse: server-sig-algs=
debug3: kex_input_ext_info: extension publickey-hostbound@openssh.com
debug1: kex_ext_info_check_ver: publickey-hostbound@openssh.com=
debug3: kex_input_ext_info: extension ping@openssh.com
debug1: kex_ext_info_check_ver: ping@openssh.com=
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug3: kex_input_ext_info: extension server-sig-algs
debug1: kex_ext_info_client_parse: server-sig-algs=
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug3: ssh_get_authentication_socket_path: path '/Users/sneaky/.bitwarden-ssh-agent.sock'
debug1: get_agent_identities: bound agent to hostkey
debug1: get_agent_identities: agent returned 1 keys
debug1: Will attempt key: macos ssh key ED25519 SHA256:somekeyhash agent
debug1: Will attempt key: /var/root/.ssh/id_rsa
debug1: Will attempt key: /var/root/.ssh/id_ecdsa
debug1: Will attempt key: /var/root/.ssh/id_ecdsa_sk
debug1: Will attempt key: /var/root/.ssh/id_ed25519
debug1: Will attempt key: /var/root/.ssh/id_ed25519_sk
debug1: Will attempt key: /var/root/.ssh/id_xmss
debug1: Will attempt key: /var/root/.ssh/id_dsa
debug2: pubkey_prepare: done
debug1: Offering public key: macos ssh key ED25519 SHA256:somekeyhash agent
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: macos ssh key ED25519 SHA256:somekeyhash agent
debug3: sign_and_send_pubkey: using publickey-hostbound-v00@openssh.com with ED25519 SHA256:somekeyhash
debug3: sign_and_send_pubkey: signing using ssh-ed25519 SHA256:somekeyhash
debug3: send packet: type 50
debug3: receive packet: type 52
Authenticated to 1.1.1.1 ([1.1.1.1]:22) using "publickey".
debug1: Requesting tun unit 2147483647 in mode 1
debug1: sys_tun_open: /dev/tun0 open failed: No such file or directory
Tunnel device open failed.
Could not request tunnel forwarding.
debug1: channel 0: new session [client-session] (inactive timeout: 0)
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: filesystem
debug3: client_repledge: enter
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:somekeyhash
debug3: client_input_hostkeys: received ECDSA key SHA256:somekeyhash
debug3: client_input_hostkeys: received ED25519 key SHA256:somekeyhash
debug1: client_input_hostkeys: searching /var/root/.ssh/known_hosts for 1.1.1.1 / (none)
debug3: hostkeys_foreach: reading file "/var/root/.ssh/known_hosts"
debug3: hostkeys_find: found ssh-ed25519 key at /var/root/.ssh/known_hosts:1
debug3: hostkeys_find: found ssh-rsa key at /var/root/.ssh/known_hosts:2
debug3: hostkeys_find: found ecdsa-sha2-nistp256 key at /var/root/.ssh/known_hosts:3
debug1: client_input_hostkeys: searching /var/root/.ssh/known_hosts2 for 1.1.1.1 / (none)
debug1: client_input_hostkeys: hostkeys file /var/root/.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: client_repledge: enter
debug3: receive packet: type 4
debug1: Remote: /root/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug3: receive packet: type 4
debug1: Remote: /root/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: set_sock_tos: set socket 3 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 SSH_AUTH_SOCK
debug1: channel 0: setting env LC_TERMINAL_VERSION = "3.5.14"
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env COLORFGBG
debug1: channel 0: setting env LANG = "en_US.UTF-8"
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env PATH
debug1: channel 0: setting env LC_TERMINAL = "iTerm2"
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env COLORTERM
debug3: Ignored env TERM
debug3: Ignored env HOME
debug3: Ignored env __CF_USER_TEXT_ENCODING
debug3: Ignored env LSCOLORS
debug3: Ignored env LS_COLORS
debug3: Ignored env PS1
debug3: Ignored env MAIL
debug3: Ignored env LOGNAME
debug3: Ignored env USER
debug3: Ignored env SHELL
debug3: Ignored env SUDO_COMMAND
debug3: Ignored env SUDO_USER
debug3: Ignored env SUDO_UID
debug3: Ignored env SUDO_GID
debug2: channel 0: request shell confirm 1
debug3: send packet: type 98
debug3: client_repledge: enter
debug1: pledge: fork
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Welcome to Ubuntu 24.04.2 LTS (GNU/Linux 6.8.0-60-generic x86_64)
Asked by MOHAMMAD RASIM (121 rep)
Jun 15, 2025, 08:54 AM
Last activity: Jul 16, 2025, 12:08 AM