按照this document中的说明，我尝试在gitlab nginx配置文件中新建一个网关，如ssh.github.com，代理gitlab SSH端口到https 443端口，nginx配置自定义文件的内容为：

server {
  listen *:80;

  server_name gitssh.mysite.com;
  server_tokens off; ## Don't show the nginx version number, a security best practice

  location /.well-known {
    root /var/opt/gitlab/nginx/www/;
  }

  location / {
    return 301 https://gitssh.mysite.com:443$request_uri;
  }

  # health checks configuration
  include /var/opt/gitlab/nginx/conf/gitlab-health.conf;

  access_log  /var/log/gitlab/nginx/gitlab_access.log gitlab_access;
  error_log   /var/log/gitlab/nginx/gitlab_error.log;
}

server {
  listen *:443 ssl http2;

  server_name gitssh.mysite.com;
  server_tokens off; ## Don't show the nginx version number, a security best practice

  ## Increase this if you want to upload large attachments
  ## Or if you want to accept large git objects over http
  client_max_body_size 0;

  ## Strong SSL Security
  ## https://raymii.org/s/tutorials/Strong_SSL_Security_On_nginx.html & https://cipherli.st/
  ssl_certificate /etc/gitlab/ssl/git.mysite.com.crt;
  ssl_certificate_key /etc/gitlab/ssl/git.mysite.com.key;

  # GitLab needs backwards compatible ciphers to retain compatibility with Java IDEs
  ssl_ciphers 'ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4';
  ssl_protocols  TLSv1.2 TLSv1.3;
  ssl_prefer_server_ciphers on;
  ssl_session_cache  builtin:1000  shared:SSL:10m;
  ssl_session_timeout  5m;

  ## Real IP Module Config
  ## http://nginx.org/en/docs/http/ngx_http_realip_module.html

  ## HSTS Config
  ## https://www.nginx.com/blog/http-strict-transport-security-hsts-and-nginx/
  add_header Strict-Transport-Security "max-age=31536000";

  # Rails sets a default policy of strict-origin-when-cross-origin, so
  # hide that and just send the one we've configured for nginx
  proxy_hide_header Referrer-Policy;
  add_header Referrer-Policy strict-origin-when-cross-origin;

  ## Individual nginx logs for this GitLab vhost
  access_log  /var/log/gitlab/nginx/gitlab_access.log gitlab_access;
  error_log   /var/log/gitlab/nginx/gitlab_error.log;

  if ($http_host = "") {
    set $http_host_with_default "gitssh.mysite.com";
  }

  if ($http_host != "") {
    set $http_host_with_default $http_host;
  }

  gzip on;
  gzip_static on;
  gzip_comp_level 2;
  gzip_http_version 1.1;
  gzip_vary on;
  gzip_disable "msie6";
  gzip_min_length 250;
  gzip_proxied no-cache no-store private expired auth;
  gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript application/json;

  ## https://github.com/gitlabhq/gitlabhq/issues/694
  ## Some requests take more than 30 seconds.
  proxy_read_timeout      3600;
  proxy_connect_timeout   300;
  proxy_redirect          off;
  proxy_http_version 1.1;

  proxy_set_header Host $http_host_with_default;
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection $connection_upgrade;
  proxy_set_header X-Forwarded-Proto https;
  proxy_set_header X-Forwarded-Ssl on;

  location ~ (/api/v\d/jobs/\d+/artifacts$|\.git/git-receive-pack$|\.git/gitlab-lfs/objects|\.git/info/lfs/objects/batch$) {
    proxy_cache off;
    proxy_pass http://gitlab-workhorse;
    proxy_request_buffering off;
  }

  location /-/grafana/ {
    proxy_pass http://localhost:3000/;
  }

  # health checks configuration
  include /var/opt/gitlab/nginx/conf/gitlab-health.conf;

  location / {
    proxy_cache off;
    proxy_pass  http://gitlab-workhorse;
  }

  location /assets {
    add_header X-Content-Type-Options nosniff;
    proxy_cache gitlab;
    proxy_pass  http://gitlab-workhorse;
  }

  error_page 404 /404.html;
  error_page 500 /500.html;
  error_page 502 /502.html;
  location ~ ^/(404|500|502)(-custom)?\.html$ {
    root /opt/gitlab/embedded/service/gitlab-rails/public;
    internal;
  }

  
}

尝试连接到服务器后，我得到这个错误：

$ ssh -vvvv git@git.mysite.com

OpenSSH_8.2p1 Ubuntu-4ubuntu0.2, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/user/.ssh/config
debug1: /home/user/.ssh/config line 1: Applying options for git.mysite.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 *
debug1: Executing proxy command: exec /usr/bin/corkscrew 127.0.0.1 3129 git.mysite.com 443
debug1: identity file /home/user/.ssh/id_rsa type 0
debug1: identity file /home/user/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.2
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: Tue, 22 Jun 2021 06:49:09 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 remote host

我知道这个问题是关于nginx配置的。有人能帮忙吗？