[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Why was exim selcted as the default MTA?

On Sun 13 Jun 1999, Craig Sanders wrote:
> On Sat, Jun 12, 1999 at 01:51:30PM -0500, Jor-el wrote:
> > Maybe our ISP's are setup differently. The debian out-of-box
> > configuration did not work for me (and I selected option (2) [for
> > smarthost relaying] during the configure). Here is what I got for 1 mail
> > prior to my "fixing" the problem :
> > 
> > 1999-06-10 01:15:58 10ry7u-0000A1-00 SMTP error from remote mailer after
> > MAIL FROM: <coder@marvin.megadodo.umb> SIZE=1371: host smtp1.ibm.net
> > []: 451 <coder@marvin.megadodo.umb>... Unresolvable domainname.
> > Contact your administrator.
> this isn't an exim issue. it's the anti-spam software on your ISP...most
> ISPs will reject mail from non-existant domains now because a) it is
> highly likely to be spam, and b) if it isn't spam, why bother accepting
> mail that doesn't have a valid reply address...better to bounce it
> immediately.

Yes, true, and I have to say I agree fully.

> even if your ISP did accept the mail from a bogus address, it is likely
> that your recipient's mailer will reject it - and you would never know
> because there is no valid address to bounce it to.
> the solution is to get yourself one of the free dynamic dns hostnames
> (e.g. dhis.org) and configure exim to use that...you'll have a hostname
> which is valid for your internal network and on the internet.

You don't have to do that; all that's required to prevent the reject
listed above is to supply a correct from address in the envelope. Note I
say "envelope", and not "from header". I'm assuming that you can also
receive email, right? So, fill in the host part from that (i.e. ibm.net)
for the envelope (you can let exim rewrite the envelope and leave the
rest alone).

You'll run into this problem no matter what MTA you use, BTW; only
alternative is to delivery directly (and not use a smarthost). However,
the remote systems you'll be connecting to, will mostly also want to see
a resolvable domain in the envelope from.

Paul Slootman
home: paul@wurtel.demon.nl | work: paul@murphy.nl | debian: paul@debian.org
http://www.wurtel.demon.nl | Murphy Software,   Enschede,   the Netherlands

Reply to: