Hello Darin,

Wednesday, December 8, 2004, 10:17:14 AM, you wrote:

DC> Yes, but in the dial world you know who is sending mail through your server,
DC> so leave port 25 open for dial users only, and have your non-dial users to
DC> send to port 587 via SMTP AUTH.

They are not forced to send through any server, they are unfiltered on
the net, I can force the ones on my local dial pool, but I have zero
control over the wholesale pools, and the abuse reports never reach
me, I don't own the IP's. If I don't know they are abusing or
compromised, how can I remove them from radius?

DC> You should be able to trace dial offenders easily through your logs and
DC> freeze their accounts if there's a problem.  Since you control the network
DC> they're using to access the internet, you can enforce security at the
DC> dial-up access level rather than at the SMTP level, which is just as good if
DC> not better.

If they send through my local dial pool, easily enough, and I do.  For
the wholesale pools, I control nothing, just radius, and as stated
before, if I am never alerted to abuse, I cannot shut them down.

DC> For those using other ISPs to connect to your mail servers, that's when you
DC> could enforce SMTP AUTH.

And I do.

DC> For monitoring customers, a simple report showing incoming and outgoing
DC> totals, ordered by volume, should show you quickly who potential offenders
DC> might be.  There's no excuse for us to say we're fighting spam and not
DC> police our own networks.  A simple report delivered nightly via email could
DC> show incoming and outgoing volume for each domain, ordered by decreasing
DC> volume.  It takes less than a minute to scan the top and make sure there are
DC> no potential problems.  That's a minute a day we can afford to ensure there
DC> are no violations we need to investigate, as well as protecting our mail
DC> servers from abuse that could affect all customers.  So I guess that,
DC> instead of not being able to afford to do it, I would argue that you can't
DC> afford _not_ to do it.

So you're saying I should put a protocol sniffer at each of my
gateways to my four upstream providers to log and analyze all SMTP
traffic, generate a report, and mail it to me?  Name a hosting
provider that is doing this?  That is not a trivial task. I can use
Cisco Routers to force SMTP traffic through mail proxies and analyze
it that way, but they will need to be pretty hefty machines, and I
don't know about your boss, but mine will take a lot of convincing to
pay for that, especially since there is very little up front cost to
responding to abuse reports.

DC> Darin.


-- 
Best regards,
 Charles                            mailto:[EMAIL PROTECTED]


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