High dnsbl lookup failure rate

We have turned on detailed dnsbl debugging, and it shows that domino 6.5.1 on win 2k fails to find dns entries that are in fact present. We can find them in a manual nslookup performed on the server, but domino cannot. Here are the details.

First, turn on detailed reporting with two set config commands:

set config smtpdebugcontrols=3

set config smtpdebugdnsbl=1

After these were on, the log recorded the following failures:

05/26/2004 07:41:01 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.dul.dnsbl.sorbs.net

05/26/2004 07:41:01 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

05/26/2004 07:41:01 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.sbl-xbl.spamhaus.org

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.bl.spamcop.net

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.list.dsbl.org

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.relays.ordb.org

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] Performing DNSBL filter lookup for 137.45.65.67.dun.dnsrbl.net

05/26/2004 07:41:02 PM SMTP Server [0560:0008-061C] DNSBL filter lookup returned status: No address associated with name

But manual nslookups in both sorbs and spamcop returned hits, using either of the DNS servers defined on the server. The listings were months old, so it was not a near miss.

We are running win 2k pro with service pack 4. Our isp is Comcast.

Can anyone explain why there would be this inconsistency? A tremendous volume of spam is getting through this malfunction.

Can we tweak win 2k or domino to make dns lookups more reliable? The only blacklist getting a high hit rate is now sbl-xbl.spamhaus.org

TIA

-Andy

Subject: high dnsbl lookup failure rate

I also noticed a similar issue - SPAMCOP all but has stopped working for us.

It used to be (by far) the #1 DNSBL.

Spamhaus reports fewer hits than it used to.

We are using:

dnsbl.sorbs.net ; bl.spamcop.net ; sbl-xbl.spamhaus.org ; opm.blitzed.org

Right now SORBS is the only one that has a decent hit rate.

We are using AT&T - and have put in the “secondary” DNS’s they recommend for DNSBL

(12.127.16.77 & 12.127.17.77).

Any ideas on whether this is Domino, Win2k or the ISP’s DNS issue?