This is because your internet address does not reverse map to the DNS domain you are sending from. You need to set your external DNS to use your NATed address, or use a dynamic DNS hosting service like dnydns or no-ip.com.
Basically, when you go to iptools.com and do a MX lookup for yourdomain.com, it should show the internet address of your ISP modem. Additionally, your IP should reverse map to yourdomain.com. Jeremiah E. Bess Network Ninja, Penguin Geek, Father of four On Sat, May 30, 2009 at 12:10, Jibz <[email protected]> wrote: > I have setup a mail server on CentOS 5 > > > sendmail-8.13 > > I'm able to sent and receive mails from yahoo and gmail. > I've another microsoft exchange server on the same network. Mails sent from > that server to my mail server gets bounced. > > I got this error in /var/log/mail > > *May 30 22:11:24 myhostname sendmail[31981]: n4UGfO5L031981: > ruleset=check_rcpt, arg1=<[email protected]>, relay= > mx1.exchangeserver.com[public IP of exchange server] (may be forged), > reject=550 5.7.1 <[email protected]>... Relaying denied. IP name > possibly forged [public IP of exchange server] > > May 30 22:11:24 myhostname sendmail[31981]: n4UGfO5L031981: > from=<usern...@exchangeserver>, size=0, class=0, nrcpts=0, proto=SMTP, > daemon=MTA, relay=mx1.exchangeserver.com [public IP of exchange server] > (may be forged)* > > As the exchange server is in my network if you do a lookup for the domain > name of that server you will get the local IP only. > > So i changed the entry of my /etc/hosts file > > and added > > <PUBLIC IP> <exchangeserver.com> > > Now still the mails bounces but a different error > > *May 30 22:42:10 myhostname sendmail[32645]: n4UHCASl032645: > ruleset=check_rcpt, arg1=<[email protected]>, > relay=mail.exchangeserverom [public IP of exchange server], reject=550 5.7.1 > <[email protected]>... Relaying denied > > > May 30 22:42:10 myhostname sendmail[32645]: n4UHCASl032645: > from=<usern...@exchangeserver>, size=0, class=0, nrcpts=0, proto=SMTP, > daemon=MTA, relay=mail.exchangeserver[public IP of exchange server]* > > Please help me out!!!! > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Linux Users Group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] For more options, visit our group at http://groups.google.com/group/linuxusersgroup -~----------~----~----~----~------~----~------~--~---
