It appears you are using *OpenConnect*, although both the strings OpenVPN and OpenConnect appear in prior posts. These are *completely different* VPN clients.
You are using an *ancient* old release of OpenConnect v7.06. The automatic MTU detection logic has been vastly improved in newer versions of OpenConnect: https://www.infradead.org/openconnect/changelog.html So yes, this is indeed a bug in OpenConnect's MTU handling, but likely one which we've long since fixed upstream. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openssh in Ubuntu. https://bugs.launchpad.net/bugs/1874257 Title: SSH fails with connection timed out - in VPN and hangs here "expecting SSH2_MSG_KEX_ECDH_REPLY" + Ubuntu 16.04.6 LTS Status in linux package in Ubuntu: Invalid Status in openconnect package in Ubuntu: Confirmed Status in openssh package in Ubuntu: Confirmed Bug description: Hello Team, SSH timeout issue, once connect to VPN. Environment ====== Dell XPS 9570 Ubuntu 16.04.6 Xenial Xerus) kernel - 4.15.0-55-generic $dpkg -l | grep -i openssh ii openssh-client 1:7.2p2-4ubuntu2.8 --> ii openssh-server 1:7.2p2-4ubuntu2.8 ii openssh-sftp-server 1:7.2p2-4ubuntu2.8 VPN tunnel info ==== vpn0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:IP P-t-P:xx Mask:255.255.252.0 inet6 addr: fe80::b8e2:bea4:2e62:fe08/64 Scope:Link UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1406 Metric:1 RX packets:962 errors:0 dropped:0 overruns:0 frame:0 TX packets:1029 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:87839 (87.8 KB) TX bytes:238740 (238.7 KB) Issue ==== Unable to connect to any host via ssh or sftp after VPN connection Tried ===== Reinstalled the openssh-client package and still no luck. May I know why the default cipher is not taking/hanging? Please let me know . There were no recent changes. Workaround === Able to connect to ssh / sftp $ssh -c aes128-ctr user@IP Below is the debug ssh client logs === ====== $ssh -vvv user@ip OpenSSH_7.2p2 Ubuntu-4ubuntu2.8, OpenSSL 1.0.2g 1 Mar 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug2: resolving "IP" port 22 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to IP [IP] port 22. debug1: Connection established. debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_rsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_ecdsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_ed25519 type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/user/.ssh/id_ed25519-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.8 debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 pat OpenSSH* compat 0x04000000 debug2: fd 3 setting O_NONBLOCK debug1: Authenticating to IP:22 as 'user' 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: curve25519-sha...@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c debug2: host key algorithms: ecdsa-sha2-nistp256-cert-...@openssh.com,ecdsa-sha2-nistp384-cert-...@openssh.com,ecdsa-sha2-nistp521-cert-...@openssh.com,ssh-ed25519-cert-...@openssh.com,ssh-rsa-cert-...@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa debug2: ciphers ctos: chacha20-poly1...@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com,aes256-...@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc debug2: ciphers stoc: chacha20-poly1...@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com,aes256-...@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc debug2: MACs ctos: umac-64-...@openssh.com,umac-128-...@openssh.com,hmac-sha2-256-...@openssh.com,hmac-sha2-512-...@openssh.com,hmac-sha1-...@openssh.com,umac...@openssh.com,umac-...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: MACs stoc: umac-64-...@openssh.com,umac-128-...@openssh.com,hmac-sha2-256-...@openssh.com,hmac-sha2-512-...@openssh.com,hmac-sha1-...@openssh.com,umac...@openssh.com,umac-...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: compression ctos: none,z...@openssh.com,zlib debug2: compression stoc: none,z...@openssh.com,zlib debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug2: peer server KEXINIT proposal debug2: KEX algorithms: curve25519-sha256,curve25519-sha...@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,diffie-hellman-group14-sha1 debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519 debug2: ciphers ctos: chacha20-poly1...@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com,aes256-...@openssh.com debug2: ciphers stoc: chacha20-poly1...@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com,aes256-...@openssh.com debug2: MACs ctos: umac-64-...@openssh.com,umac-128-...@openssh.com,hmac-sha2-256-...@openssh.com,hmac-sha2-512-...@openssh.com,hmac-sha1-...@openssh.com,umac...@openssh.com,umac-...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: MACs stoc: umac-64-...@openssh.com,umac-128-...@openssh.com,hmac-sha2-256-...@openssh.com,hmac-sha2-512-...@openssh.com,hmac-sha1-...@openssh.com,umac...@openssh.com,umac-...@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: compression ctos: none,z...@openssh.com debug2: compression stoc: none,z...@openssh.com debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug1: kex: algorithm: curve25519-sha...@libssh.org debug1: kex: host key algorithm: ecdsa-sha2-nistp256 debug1: kex: server->client cipher: chacha20-poly1...@openssh.com MAC: <implicit> compression: none debug1: kex: client->server cipher: chacha20-poly1...@openssh.com MAC: <implicit> compression: none debug3: send packet: type 30 debug1: expecting SSH2_MSG_KEX_ECDH_REPLY << Hangs here >> Please shed some views Thanks Jay To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1874257/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
