Problem sending out mail from Sendmail
 

Dear fellow Members,

Would like to seek assistance from all of you, I am using Redhat 9.0 server with sendmail application activated as our mail server. Last few days we encountered sending problem to any of the email address or mail domains. Before that was okay all the while. We have been check through the configuration compare to before (as we do have another same setup of server and service), still unresolvable. If you have encountered such problems and able to rectify, kindly advise.

Thank you.

Is this a home webserver? Or is it a dedicated/co-located server? I need more information. Also make sure you have a reverse IP set up. If your server name is server1.yourdomain.com, then server1.yourdomain.com needs to resolve in the DNS. Other wise the email is going to bounce.

If you could post the domain name that this server provides service for, or PM me a test mail address, I can setup a watch on my server when you try to send to it and probably tell you what the problem is. As Soulwatcher says, the most common problems are connected with missing RDNS entireis and the server not having a hostname. But also, check that the server uses a fully qualified domain name in its EHLO and that it is not configured as an open relay. If it is an open relay, then the chances are that your server has been used for spaming, and it is now listed in a DNS blacklist.

You might also want to try running the main domain through the checks at http://www.dnsreport.com it will usually give you a pretty good idea if there is a DNS related problem causing mailserver issues.

Is there a error bounced back? If so that will have some helpful information sometimes in it.

I also have problems with my mail server, most hosts are rejecting me E-mails. I found out that I need to set the RDNS but unfortunately I don't know how to do that via Webmin.

I also do not have a domain name set to my server yet.

Any suggestions are appreciated.