There could be many RBL's in your config (we have about 100 in ours...which
we probably need to prune since many don't add any real value), each of
which would require a DNS hit for each message.

Best just to set up your own DNS server and be done with it.

Darin.


----- Original Message ----- 
From: "Kevin Rogers" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, March 31, 2005 5:03 PM
Subject: [Declude.Virus] Covad has a problem with our RBL


I received the following email today from Covad - our access provider.
It looks like they have a problem with Declude checking inbound emails
against a realtime blackhole list.  (The problem could also be several
emails we've received lately with hundreds of recipients, many of which
were invalid - so it could be the NDR problem mentioned).

Does anyone know if Declude, setup normally without much modification,
is using more than 1 RBL, or, irregardless of how many it uses, would it
be checking the RBL 12000 times an hour for a mail server that delivers
about 6000 messages a day?  Or do you think this most likely has to do
with the too-many-invalid-recipients problem?

Thanks.  Kevin

MESSAGE FOLLOWS
-------------------------------
Dear Covad Customer,

Our records indicate that your computer has made 12497 requests during
the hour we monitored it which accounted for 5.13% of the total traffic
to the Covad nameservers in your region. The high volume of requests
made by your computer to our nameservers causes a degradation of service
for other Covad customers.

The IP address implicated is:

XX.XXX.XXX.XXX

Possible causes for this excessive activity includes, but not limited to
the following reasons:

-Virus infected computer(s) sending infected emails which causes Covad
servers to receive MX queries for every infected message.
-Computer hosting an open proxy or relay that is being abused by a
spammer.  Each outbound email will generate a DNS request.
-Mail server configured to check every inbound email on a realtime
blackhole list (RBL).  This could oppose a problem if there are more
than two lists being queried.
-Mail server configured to send a non delivery receipt (NDR) for every
email received at an invalid email address.  NDR messages cause Covad
servers to receive DNS requests as well as generate unnecessary traffic
on a customer's network.  NDR messages is also a way for spammers to
confirm valid email addresses which could cause mail servers to receive
even more spammed emails.

---
[This E-mail was scanned for viruses.]

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