Websocket is not working with Nginx Reverse Proxy

[Sergey A. Osokin]

Hi,

On Sun, Sep 19, 2021 at 01:35:02PM -0400, blason wrote:
> Hi Team,
> 
> I am trying to add nginx reverse proxy behind Check Point Mobile access
> portal which is a SSL VPN portal. Somehow this not working and when I
> captured and analyzed the har file I observed that the portal is accepting
> websocket calls. I tried implementing the same with nginx but I am still
> unable to find the solution.
> 
> Here is what I am seeing with Har file and then I have given my config
> 
> ################
> General:
> Request URL:
> https://vpn.xxxx.com/7D8B79A2-8974-4D7B-A76A-F4F29624C06BMCNu92Dm4l-Zi00Q9XmCAEP2W0TG236BR4s3ROIfxiy7ICrrEllGkIikmth2jOjkklZMt4z1porwm5BgBNByrQ/websocket?url=https%3A%2F%2Fvpn.xxxx.com%2FPortal%2FMain&nocache=1632059231484HTTP
> Version: HTTP/1.1Request method: GET
> Headers:
> Cache-Control no-cache
> Connection Upgrade
> Cookie selected_realm=ssl_vpn;
> CPCVPN_SESSION_ID=e27df7fe2b0ce359198a5b703b9402d235668bb3;
> CPCVPN_BASE_HOST=vpn.xxxx.com;
> CPCVPN_OBSCURE_KEY=23f63321355ce5d11767b258178d9775
> DNT 1
> Host vpn.xxxx.com
> Origin https://vpn.xxxx.com
> Sec-WebSocket-Key ehTLIcXsKwaddkSug5rN9Q==
> Sec-WebSocket-Version 13
> Upgrade websocket
> User-Agent Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like
> Gecko
> Query arguments:
> url https://vpn.xxxx.com/Portal/Main
> nocache 1632059231484
> ##############################
> 
> And here is my config
> 
> *************************
>    upstream websocket {
>         server vpn.xxxx.com:443;
>     }
> server {
>         listen 443 ssl;
>         server_name  vpn.xxxx.com;
>         ssl_protocols  TLSv1.2;
>         ssl_prefer_server_ciphers on;
>         ssl_session_cache shared:SSL:10m;
>         ssl_certificate           /etc/nginx/ssls/labcerts/wild.crt;
>         ssl_certificate_key      /etc/nginx/ssls/labcerts/wild.key;
>         ssl_ciphers
> 'ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS';
>         ssl_dhparam /etc/ssl/dhparams2048.pem;
>         add_header Strict-Transport-Security "max-age=31536000;
> includeSubDomains; preload" always;
>         ssl_session_timeout 1d;
>         ssl_session_tickets off;
>         ssl_stapling on;
>         ssl_stapling_verify on;
>         resolver 8.8.8.8 8.8.4.4 valid=300s;
>         access_log /var/log/nginx/sslvpn/access.log;
>         error_log /var/log/nginx/sslvpn/error.log;
>         error_page 404 403 /custom_404.html;
>         location = /custom_404.html {
>         root /usr/share/nginx/html;
>         internal;
>         }
> location /SNX/ {
>         proxy_pass https://websocket;
>             proxy_http_version 1.1;
>             proxy_set_header Upgrade $http_upgrade;
>             proxy_set_header Connection $connection_upgrade;
>                 proxy_set_header Host $host;
> }
> location  / {
>         proxy_send_timeout   90;
>         proxy_http_version 1.1;
>         proxy_read_timeout   90;
>         proxy_connect_timeout 30s;
>         proxy_pass https://websocket;
>         proxy_set_header Upgrade $http_upgrade;
>         proxy_set_header Connection $connection_upgrade;
>         proxy_ssl_server_name on;
>         proxy_redirect off;
>         proxy_set_header   Host   $host;
>         proxy_set_header   X-Real-IP  $remote_addr;
>         proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
>         }
> }
> ********************************************

Could you try to slightly update your configuration to the
"more sophisticated example" as it's descibed on
http://nginx.org/en/docs/http/websocket.html

-- 
Sergey Osokin