sendmail's outgoing IPs

[Wojciech Puchar]

> > something like "T1" here costs far too much to dedicate it just for mails.
> >
> > for the same price i can get four "4Mbit/s" ADSL's (which i have now),
> > that actually gives 4Mbit/s download speed, but only 512kbps upload.
>
> Lucky you.  We have a 1500/256kbps link for up to 20 boxes, though
> there's talk of upgrading to (nominally) 8M/384kbps.

i have 300 users. and all works quite fast :)

> > if you substract ACK's needed for 4Mbit/s download, little is left.
>
> Slight exaggeration, though TCP downloads do need say 5-10% of download

count 10 as HTTP requests can be large. that's 400kbit/s from 512 
available!

> bandwidth upstream.  Sure, as soon as you use all upload bandwidth (your
> mail example, torrents of course, youtube uploads etc) your download

ipfw rules make sure upload bandwidth isn't saturated. it's just a problem 
that few is left for something else

> > is a problem now.
>
> Why not add dummynet pipes and suitable rules to limit the outbound
> bandwidth for mail (or torrents, whatever's a problem) to a maximum of
> say 80% of upload, so for 512k set upload limit to maybe 400k, leaving

i am already doing this.