[CentOS] Sendmail problem

[Thomas E Dukes]

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Johnny Hughes
> Sent: Wednesday, April 12, 2006 7:28 AM
> To: CentOS ML
> Subject: RE: [CentOS] Sendmail problem
> 
> 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.

Hey Johnny,

Yes, I know.  I have that problem sending mail to AOL (that's ironic) and
RoadRunner accounts.  If my ISP hadn't lost its mind for what they charge
($180/month) for a static/business DSL account, I would be on that.

Thanks!!
>  
>