DNS requests via SSH tunnel stopped working.

Hello!

I was using SSH tunnel to get access to the Internet from my office (Mikrotik at home as a http-proxy).
Everything was working fine untill… I guess it was an ROS upgrade, but I cannot tell which because I don’t use this tunnel very often. Just spotted an hour ago it is not working.

The situation looks like this:

  • on ROS: SSH is running on port 23 (a lot of robots were trying my password)
  • on ROS: there is a REDIRECT from port 53 to port 23 (office firewall accepts all outgoing on port 53)
chain=dstnat action=redirect to-ports=23 protocol=tcp src-address-list=TrustedWAN in-interface=ether1-gateway dst-port=53
  • on ROS: “:log info [:resolve google.com]” - gives me an answer. DNS from PCs from LAN at home are working (ROS as primary, 8.8.8.8 as secondary)
  • on ROS: proxy enabled:
/ip proxy> print
                 enabled: yes
             src-address: 0.0.0.0
                    port: 8118
            parent-proxy: 0.0.0.0
       parent-proxy-port: 0
     cache-administrator: webmaster
          max-cache-size: none
           cache-on-disk: no
  max-client-connections: 600
  max-server-connections: 600
          max-fresh-time: 3d
   serialize-connections: no
       always-from-cache: no
          cache-hit-dscp: 4
             cache-drive: system
  • on office PC: Putty - SSH - Tunnels: ipv4 local 58118:localhost:8118 (and two other tunnels redirecting traffic to my PC in LAN at home)
  • on office PC: localhost:58118 as proxy in my browser.

Now, whenever I try to visit a webpage I get

may/28/2012 10:01:26 ssh,error [[MY_PREFIX]]: unable to resolve hostname

I think something was upgraded too much in recent releases of ROS. Now I’m using 5.15, but as I said before - this change could be few versions earlier.

Please tell me is there a chance for me to fix it myself ? What to check?

I think it’s fixed in ros 5.21.