Can not open localhost in browser with ssh port forwarding

Aii Aii

7/22/24, 5:07 PM

I have an issue with access to web page that opens via ssh port forwarding: I do:

ssh [email protected] -L 7182:10.1.11.82:80

172.22.123.71 is a PC which has access to srever's 10.1.11.82 network

Then I open in browser localhost:7182 or 127.0.0.1:7182 and I get 127.0.0.1 refused to connect error.

I check in CLI:

$ telnet localhost 7182

Escape character is '^]'.

HTTP/1.0 400 Bad Request Content-Type: text/html Content-Length: 345 Connection: close Date: Sat, 22 Jul 2023 16:48:49 GMT Server: HTTP Server
"-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 400 Bad Request
400 Bad Request
Connection closed by foreign host.Trying 127.0.0.1... Connected to localhost.

It means that ssh forwarding is working. In CLI remote server opens the connection via localhost port 71 82. So the issue is local. I don't use any firewall or iptables or proxy on my Ubuntu 20.04. It is the same for 3 browser FF, Chrome, Brave. I tried to clear cookies. Also when I try the same om similar but different host it works.

I will be very grateful for any clue! As this problem is very annoying.

Erorr in browser

$ sudo netstat -tulpn | grep 7182

tcp        0      0 127.0.0.1:7182          0.0.0.0:*               LISTEN      34957/ssh           
tcp6       0      0 ::1:7182                     :::*               LISTEN      34957/ssh

Also I've noticed that when I try it in browser the port number disappears in address line. But when I try some localhost port that has no listener the port number does not disappear.

0 + 3

ssh

browser

localhost

port-forwarding

waltinator

7/22/24, 10:02 PM

Read `man ssh`, and use one of the `-X` or `-Y` options to pass the Windowing environment.

Aii Aii

7/23/24, 12:32 PM

Thank you for your input, waltinator! But it has nothing common with X11 forwarding. The issue is exactly between browsers and localhost.

Aii Aii

7/23/24, 12:50 PM

In my PC's netstats output I see port listener 127.0.0.1:7182. In telnet output above you can see response from web server on 10.1.11.82. So via CLI the connection works. Probably with Curl the server's output could look better. I just have no idea how can I debug it between browser and localhost.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Can not open localhost in browser with ssh port forwarding

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