I am seeing veeeeeerry slow feedback on remote ssh terminals to a new install of Ubuntu 16.04. E.g., after typing a character it may take 20-30 seconds before it is displayed in the terminal. Initial login with password to the server is fast, just subsequent keyboard entry is slow. Other applications (mysql, nginx) show good performance, so this seems to only affect ssh.
The server is on the local network, and ping latency client->server and server->client varies between 1ms and 300ms depending on traffic, so network latency is not the cause of the delays. Traceroute shows no issues.
The server is not busy, and local sessions have good performance, so server resources are not the cause of the delays.
I have tried adding entries to hosts files on both client and server. I have tried switching the client from DHCP to static IP/gateway/DNS. I tried with
ssh -v (below) and also
I'm looking for suggestions on how to debug this issue and get ssh terminal performance back to a usable level. Any suggestions welcome.
Roberts-MacBook-Pro:~ regeier$ ping 192.168.1.111 PING 192.168.1.111 (192.168.1.111): 56 data bytes 64 bytes from 192.168.1.111: icmp_seq=0 ttl=64 time=2.565 ms 64 bytes from 192.168.1.111: icmp_seq=1 ttl=64 time=2.184 ms 64 bytes from 192.168.1.111: icmp_seq=2 ttl=64 time=2.259 ms ^C --- 192.168.1.111 ping statistics --- 3 packets transmitted, 3 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 2.184/2.336/2.565/0.165 ms Roberts-MacBook-Pro:~ regeier$ ssh -v email@example.com OpenSSH_6.9p1, LibreSSL 2.1.8 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 21: Applying options for * debug1: /etc/ssh/ssh_config line 56: Applying options for * debug1: Connecting to 192.168.1.111 [192.168.1.111] port 22. debug1: Connection established. debug1: identity file /Users/regeier/.ssh/id_rsa type 1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_ecdsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_ed25519 type -1 debug1: key_load_public: No such file or directory debug1: identity file /Users/regeier/.ssh/id_ed25519-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.9 debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 pat OpenSSH* compat 0x04000000 debug1: Authenticating to 192.168.1.111:22 as 'ubuntu' debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client firstname.lastname@example.org <implicit> none debug1: kex: client->server email@example.com <implicit> none debug1: expecting SSH2_MSG_KEX_ECDH_REPLY debug1: Server host key: ecdsa-sha2-nistp256 SHA256:2v5V8cSY2r2DLlfxdNJ6M1zw0yk467wLQiUof0/t1so debug1: Host '192.168.1.111' is known and matches the ECDSA host key. debug1: Found key in /Users/regeier/.ssh/known_hosts:4 debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,password debug1: Next authentication method: publickey debug1: Offering RSA public key: /Users/regeier/.ssh/id_rsa debug1: Authentications that can continue: publickey,password debug1: Trying private key: /Users/regeier/.ssh/id_dsa debug1: Trying private key: /Users/regeier/.ssh/id_ecdsa debug1: Trying private key: /Users/regeier/.ssh/id_ed25519 debug1: Next authentication method: password firstname.lastname@example.org's password: debug1: Authentication succeeded (password). Authenticated to 192.168.1.111 ([192.168.1.111]:22). debug1: channel 0: new [client-session] debug1: Requesting email@example.com debug1: Entering interactive session. debug1: client_input_global_request: rtype firstname.lastname@example.org want_reply 0 debug1: Sending environment. debug1: Sending env LANG = en_AU.UTF-8 Welcome to Ubuntu 16.04.1 LTS (GNU/Linux 4.4.0-31-generic x86_64) * Documentation: https://help.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/advantage 0 packages can be updated. 0 updates are security updates. Last login: Fri Jan 27 20:47:02 2017 from 192.168.1.3