Sendmail: problems mailing to external internet addresses

[Dawn Rourke]

Hello,
we have successfully configured SAP and UNIX to send messages to external internet address via Sendmail (HP-UX 11.0, Sendmail 8.8.6, Non-DNS environment). The problem we have now, is that some messages sent to external addresses will not be delivered.

For example, a message was sent to 7 external internet addresses at the same time. 5 successfully arrived but 2, sent to addressess at netscape.net and iname.com were not delivered. We assumed that the cause of this was anti-spamming technology at netscape and iname blocking messages without a valid domain name. We have rectified this situation but messages are still not being delivered. We are getting no error messages whatsoever. Has anyone come across this problem before? Any help would be much appreciated.

regards,
Dawn

[Stefan Farrelly]

Weve seen problems like this before as well. The problem is there are so many external email servers on the net and they are all configured differently. Some are very good and can discern that your emails from your unix server actually come from some sort of account, like root or a user, and from the hostname of your unix server - rather than coming from what they expect which is Joe.Bloggs@internetdomainanme.com

What we had to do was set up a sort of spoof from our HP server which sends mail to the world.
Is in /etc/mail and its called userdb. in this file we have;
default:mailname
root:mailname root
root:maildrop root
:mailname

Then you need to create a database file from it;
makemap btree userdbThen restart sendmail. Now try sending out your emails and if some smart server out there does a mail check (anti-spam) to check the user and domain to see if its valid it should pass that check and be delivered.

As a side note - these non delivered mails, what entry is in the /var/adm/syslog/mail.log for them ? does it say Sent or...

[Dawn Rourke]

Many thanks for the response Stefan. I have done what you suggested but it doesn't appear to have resolved the problem. I was initially getting errors when using makemap (i.e.makemap: userdb.db: line 1: no RHS for LHS default:netscape.net) until I realised that I should have been putting in spaces after the colon (except on line 3). One question, should I be using the word mailstop in line three or replacing it with something meaningful? I have also tried the process with a number of different domain names, hence the time taken to respond. Should the effect of your recommendations have been to change the name & format of the sender of the message? Looking at the routing details for messages delivered to other addresses, the sender is still defined as being root@hostname.co.uk.

Entries in mail.log for the messages that aren't delivered always have a status of Sent.

regards,
Dawn

[Dawn Rourke]

Hello, having patched the gaps in our knowledge with the aid of the O'Reily Sendmail manual, we have moved on a great deal since the previous response. Messages are now being sent as expected. In order to get it to work on our system, the format of the userdb file had to be as follows.

:default:mailname domainname.co.uk
root:mailname user.name@domainname.co.uk
user.name:maildrop root

Unfortunately, despite our best efforts, messages are still not getting through to all addresses.