I am in Ubuntu 20.04.2 LTS telling this because looks like this version has encryption issues. Today I created a key that's perfectly working on but gives kex_exchange_identification: Connection closed by remote host for private GitLab domain here is the .ssh config file
Host gitlab.com Hostname altssh.gitlab.com User git Port 443 PreferredAuthentications publickey IdentityFile ~/.ssh/id_ed25519 # Private GitLab instance Host gitlab.ebpearls.com Hostname gitlab.ebpearls.com User git Port 443 PreferredAuthentications publickey IdentityFile ~/.ssh/id_ed25519 here is the full log
ssh -Tvvv git@gitlab.<mycompanydomain>.com OpenSSH_8.2p1 Ubuntu-4ubuntu0.3, OpenSSL 1.1.1f 31 Mar 2020 debug1: Reading configuration data /home/nabin/.ssh/config debug1: /home/nabin/.ssh/config line 9: Applying options for gitlab.ebpearls.com debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files debug1: /etc/ssh/ssh_config line 21: Applying options for * debug2: resolving "gitlab.ebpearls.com" port 443 debug2: ssh_connect_direct debug1: Connecting to gitlab.ebpearls.com [mycompanyip] port 443. debug1: Connection established. debug1: identity file /home/nabin/.ssh/id_ed25519 type 3 debug1: identity file /home/nabin/.ssh/id_ed25519-cert type -1 debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.3 debug1: kex_exchange_identification: banner line 0: HTTP/1.1 400 Bad Request debug1: kex_exchange_identification: banner line 1: Server: nginx debug1: kex_exchange_identification: banner line 2: Date: Wed, 06 Oct 2021 06:50:54 GMT debug1: kex_exchange_identification: banner line 3: Content-Type: text/html debug1: kex_exchange_identification: banner line 4: Content-Length: 150 debug1: kex_exchange_identification: banner line 5: Connection: close debug1: kex_exchange_identification: banner line 6: debug1: kex_exchange_identification: banner line 7: <html> debug1: kex_exchange_identification: banner line 8: <head><title>400 Bad Request</title></head> debug1: kex_exchange_identification: banner line 9: <body> debug1: kex_exchange_identification: banner line 10: <center><h1>400 Bad Request</h1></center> debug1: kex_exchange_identification: banner line 11: <hr><center>nginx</center> debug1: kex_exchange_identification: banner line 12: </body> debug1: kex_exchange_identification: banner line 13: </html> kex_exchange_identification: Connection closed by remot 1 Answer
Thats because private gitlab repo doesn't allow ssh from 443 and ISP doesn't allow port 22 for ssh. For those private repo which allow 443 this solution will work. I should be looking for some Jump server sloution where I can use the middle jump server's port 443 then ssh to port 22 of targeted server from there.
