Bart Spearen
asked on
Sendmail - HPUX - Sending mail - Some are delivered, Some are not
I have a HPUX system and I am using Sendmail on there. The system generates around 500 email daily, however, emails to a certain domain, say @abe.com, do not reach the recipient's email inbox. I also use an alias that does not have a public domain - so my domain try.com - is only seen behind a few firewalls that I do not control. try.com is not public facing and therefore, does not have a MX record in DNS.
When first researching this issue, it was discussed maybe @abe.com firewall was dev null these emails because it has a rule to check the DNS for a valid MX record and if one isn't found, it believes it is SPAM and kills it. Sounds feasible, but where would you look to see if the firewall actually has this rule?
Could there be anything else? the Sendmail logs state that emails are sent successfully or at least sent. There are no rejection messages that I can see in my logs. However, the abe.com domain's log doesn't have any entries that a mail message was parsed from try.com and sent to dev null.
Any ideas?
Thanks.
When first researching this issue, it was discussed maybe @abe.com firewall was dev null these emails because it has a rule to check the DNS for a valid MX record and if one isn't found, it believes it is SPAM and kills it. Sounds feasible, but where would you look to see if the firewall actually has this rule?
Could there be anything else? the Sendmail logs state that emails are sent successfully or at least sent. There are no rejection messages that I can see in my logs. However, the abe.com domain's log doesn't have any entries that a mail message was parsed from try.com and sent to dev null.
Any ideas?
Thanks.
Jan Bacher
What happens when you telnet to port 25 and query the mail server manually?
It's really tough to debug this sort of problem using example domain names.
Best anyone can do, without real domain names for testing, is for you to disable any type of mail mucking (spam filtering, firewalling, anything) on domains which aren't receiving email + then get into your logs + start sending test email, while your camped on the MTA logs sending mail + mail logs where mail should be received.
Then start enabling all the facilities you disabled, one by one, till you find the problem area, so you know what to debug.
Very simple to do. Also very tedious (time consuming).
Best anyone can do, without real domain names for testing, is for you to disable any type of mail mucking (spam filtering, firewalling, anything) on domains which aren't receiving email + then get into your logs + start sending test email, while your camped on the MTA logs sending mail + mail logs where mail should be received.
Then start enabling all the facilities you disabled, one by one, till you find the problem area, so you know what to debug.
Very simple to do. Also very tedious (time consuming).
The first thing that I would do is manually duplicate the process. Quick, easy, painless, and no configuration changes necessary. You should see what the problem is during this process.
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