Exim - limit outgoing connetions on 25 port or emails per second

[JohnyByk]

Hi.

Sometimes, when users send a lot email we have problem with emails delivery because our ISP limiting outgoing connections from port 25 to 5 per second.
Maybe somone know that is possible to limit Exim to sending 3-4 emails per second?

If it's not possible we must change ISP but it's not so simple .

Regards

 

[Richard G]

Have your users use smtp authentication and use port 587 (or with ssl port 465) for outgoing mail.
Then only scripts are using port 25.

Another way is to disable outgoing mail via port 25 via CSF for example. However, also in that case users have to switch to port 587.

And a third way is limit the amount of mail they can send per hour via the virtual limits. However, this can nog be set up per second if I'm correct.

 

[JohnyByk]

I need to clarify my issue. I mean connections between my exim and external SMTP servers. Maybe i'm wrong but that connections are made on port 25. Correct me if I'm wrong.

ISP from my server room says that SYN connections on 25 port limited to 5 per second. When exim reach the limit in log appears errors:

Unable to connect to remote host: Connection refused

Maybe my configuration is wrong and i should set another port in exim (587)? I'mt not sure so if not reserved for client only?

Regards

 

[JohnyByk]

OK, im know that a lot of SMTP servers accept incoming connections only on port 25.

Now im trying change configuration for theese parameters:
queue_run_max
remote_max_parallel

Probally i tweaked that values to high. Maybe smaller values solve the problem (they should).

 

[Richard G]

I mean connections between my exim and external SMTP servers.

Oooh MTA to MTA traffice is on port 25 yes.

As for the other limit, maybe @zEitEr has some idea about that. I think he did something similar in the past by customizing exim and/or exim.pl.

Or the value's you're talking about.