hello all, there is something that bothering me like telneting to my sendmail server on port 25. people i do not know can send this way mail through my server. i want to block that. whatever menipulation on the fw didn't help neither stopping telnet service i would be gratefull for help, tnx ronen

Stopping the telnet service on your machine will not affect anyone trying to telnet into port 25 as telnet runs on port 23. You want to prohibit relaying of messages. You should be able to fine trusted domains allowed to use your sendmail config files. Depending on your version of sendmail I think the file you want to edit is /etc/mail/relay-domains. How have you tested this? Have you actually tried telnetting in yourself from outside your local network?

helo 3Dave, i tried it from outside the sendmail server. i wonder if the 'relay-domains' option tells the server who can telnet to it or what domain should it send mails. if its the second option haw can u guess to what domains u will send mails, there are thousands of them... tnx ronen

The relay-domains file should contain a list of domains that you wish to be able to send mail through your server. This should generally only contain your local network, you will have to add the IP/domain to someone outside of the network to allow them access. An example file would be: 192.168.0 RELAY foo.org RELAY bar.com RELAY This would allow for the local machines on the 192.168.0.XXX network as well as ones in the foo.org and bar.com domains to send mail.

tnx 3DAVE