In my office I am running a linux server with RH AS just installed. This server runs sendmail and sshd. If I am logged into the machine, sendmail runs fine. It does not relay, of course.

From a machine at home I want to use the linux server's sendmail in a secure way to relay.

So, as root, I do the following

ssh -v -N -L 25:SERVERIP:25 myuserid@SERVERIP

I am then prompted for my server's password. This yields

debug1: Authentication succeeded (password).
debug1: Connections to remote port 25 forwarded to local address SERVERIP:25

This seems fine.

I then tell my local mail client to send mail to port 25 on localhost. But, the ssh log shows the following when I send mail from the remote client:

debug1: channel 2: new [direct-tcpip]
channel 2: open failed: connect failed: Connection refused
debug1: channel_free: channel 2: direct-tcpip: listening port 25 for SERVERIP port 25, connect from ::1 port 58111, nchannels 3

Can anyone help on this? I have no idea what port 58111 is doing here, and I suspect this is causing the problem.

Thanks!

Your command should be

ssh -L 25:localhost:25 myuserid@SERVERIP

you are creating a socket 25 on local host to forward it to remote serverip on 25.

After this debug like

telnet localhost 25

telnet serverip 25

you should see smtp welcome message.


It should be worth noting that your connection is encrypted between home and office but the mail going out from your sendmail would be unencrypted.


[ Ideally you should build TLS support on your sendmail and authenticate people who want to relay through your sendmail ]


hope this helps.

Thanks! That did the trick.

mh