On Wed, 2006-04-12 at 07:13 -0400, Thomas E Dukes wrote: > > > -----Original Message----- > > From: centos-bounces at centos.org > > [mailto:centos-bounces at centos.org] On Behalf Of Alexander Dalloz > > Sent: Wednesday, April 12, 2006 7:06 AM > > To: CentOS mailing list > > Subject: RE: [CentOS] Sendmail problem > > > > Am Mi, den 12.04.2006 schrieb Thomas E Dukes um 2:23: > > > > > Here'sanother bounce email: > > > > > > The original message was received at Tue, 11 Apr 2006 > > 19:16:44 -0400 > > > from localhost.localdomain [127.0.0.1] > > > > > > ----- The following addresses had permanent fatal errors ----- > > > <xxxxxx at comcast.net> > > > (reason: 521-EHLO/HELO from sender 71.31.91.127 does not map to > > > localhost.localdomain in DNS) > > > > > > ----- Transcript of session follows ----- ... while talking to > > > gateway-s.comcast.net.: > > > >>> MAIL From:<apache at localhost.localdomain> SIZE=2176 > > > <<< 521-EHLO/HELO from sender 71.31.91.127 does not map to > > > localhost.localdomain in DNS <<< 521-sending machine name must be > > > provided as a fully <<< 521-qualified domain via EHLO/HELO command. > > > <<< 521-see section 4.1.1.1 and 4.1.4 of RFC 2821 <<< 521 > > 521: Comcast > > > requires that all mail servers must have a PTR record with a valid > > > Reverse DNS entry. Currently your mailserver does not fill that > > > requirement. For more information, refer to: > > > http://www.comcast.net/help/faq/index.jsp?faq=Email118405 > > > 554 5.0.0 Service unavailable > > > > 2 things: > > > > 1) Your mail host at that time of the mail had the hostname > > localhost.localdomain, thus your Sendmail used it for > > EHLO/HELO. You fixed that meanwhile > > > > 2) The remote side requires not only a valid forward DNS > > record (palmettodomains.com points to that IP) but too a > > matching reverse one. > > From here I can't judge whether the named IP is static and > > thus assigned by your ISP. If that is the case then you > > really should take care for both types of DNS entries. If not > > (you are on an dynamic line) you should use your ISP's mail > > host as SMART_HOST within your Sendmail configuration. DynDNS > > is a very bad base for reliable mail services. > > > > Alexander > > Hello Alexander, > > Yes, I have a dynamic IP address. If I use my ISPs mail host as the > SMART_HOST, would that cause relaying problems? I tried that on the mail > client end a while back and got errors about relaying. > > Thanks, I'll give it a try. Just as a side note here ... the majority of mail servers now use a technique called Realtime Blackhole List (RBL). Many of the new lists contain the IPs of all dynamic Cable/DSL providers as a huge amount of spam is sent via broadband PC's that have been compromised. It is a losing proposition to use dynamic machines to send reliable e- mail as a server ... at least that has been my experience. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 189 bytes Desc: This is a digitally signed message part URL: <http://lists.centos.org/pipermail/centos/attachments/20060412/f7aeedc9/attachment-0004.sig>