Re: [vps-mail] VPS(1) - outgoing e-mail being limited

[Bennett Lanford <benlanford@xxxxxxxxx>]

On 9/9/05, Mike Skimin <webmaster@xxxxxxxxxxxxxxxx> wrote:
> 
> Hello,
> 
> I have a client who is on a VPS(1)B server, they recently moved and are
> now connect through a local college's network. They are now unable to
> send messages to more than 8 people at a time. Other clients on the
> server are not having the problem. The college's tech team tells me
> they have updated their Firewall to allow this client to access port 25
> on our server. Their tech people believe it is our issue, I don't think
> it is because no other clients are having the problem.
> 
> Anyone know of a way to solve this issue? 


By any chance does your sendmail macro configuration file have a line like:

define(`confMAX_RCPTS_PER_MESSAGE', `8')

If it does, that would *definitely* cause the behavior you describe. 
(Unfortunately, sendmail doesn't descriminate between wannabee spammers that 
connect to your server to carry out a dictionary attack and legitimate 
clients who want to use your server as the outgoing SMTP server.0

I can't imagine the client's
> computers are limiting the number of messages, and I want to believe the
> tech team but I am at a loss as to what might be happening. I looked at
> the sendmail.cf <http://sendmail.cf> file and do not see any limiting 
> information.


The corresponding line in the sendmail.cf <http://sendmail.cf> would be

O MaxRecipientsPerMessage=8

Any ideas would greatly be appreciated.


I'll think on it ...

(P.S. Do you implement any of the techniques mentioned at 
http://technoids.org/dossed.html? Depending on the number of external IP 
addresses at the college, if several clients simultaneously use your VPS as 
their outgoing SMTP server, it is possible that all of them could look like 
they are coming from the same IP address, and sendmail might be limiting 
them someway ... Just a thought.)

-- 
Bennett Lanford <benlanford@xxxxxxxxx>

There are 10 kinds of people: those that understand binary and those that 
don't.