[Pkg-exim4-users] Throttle or limit deliveries to smarthost?

[Alex King]

Marc Haber wrote:
>> I only use a single smart_host for outside deliveries, and I want to
>> prevent flooding of my internet connection or smarthost when I send
>> mail to a distribution list.
>>     
>
> If you are delivering via a smarthost, your exim will anyway only send
> out a single copy of the message with the appropriate envelope.
>
> Greetings
> Marc
>
>   

I think this is not always the case. I think Mailman for example splits 
the distribution list into batches and sends several different mails 
with no more than a configurable number of recipients (100 by default 
IIRC). Also some (many?) ISPs mailservers now limit the number of 
recipients on a single message to 100 or less as a way to reduce spam.


I had a similar problem where a mailserver wasn't sending to a smarthost 
but directly using DNS lookups, and it sometimes killed the internet 
connection when a client host sent out large mail-list messages to many 
destinations. The best answer in the end was to rate limit the outgoing 
traffic on port 25 using tc (the linux traffic control tool).

Cheers,

Alex