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Resolving for URLsInMAPS

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: http://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=6778
Printed Date: 23 October 2017 at 5:41am


Topic: Resolving for URLsInMAPS
Posted By: yapadu
Subject: Resolving for URLsInMAPS
Date Posted: 23 November 2009 at 9:01am
I see this type of thing in my logs often (hundreds and hundreds of times a day).

Resolving for URLsInMAPS: www..facebook.com
Resolving for URLsInMAPS: www..bpnews.net
Resolving for URLsInMAPS: www.=
Resolving for URLsInMAPS: www.carsguide.com=
Resolving for URLsInMAPS: www.carsguide.c=
Resolving for URLsInMAPS: emai=
Resolving for URLsInMAPS: email.enew=
Resolving for URLsInMAPS: =
Resolving for URLsInMAPS: email.enewslt=

Obviously they are not valid URL's, so they are usually followed by an error like this:

Error occurred during URLsInMAPS: DNS Server Reports Query Name Error

Of course the system does also find URL's that are possible, but it seems odd that it picks out these and tries to check them.



Replies:
Posted By: LogSat
Date Posted: 23 November 2009 at 10:51pm
yapadu,

SpamFilter picks up various href tags embedded in HTML emails, both linking to URLs and to images. Sometimes the hrefs are encoded, other times they are simply incorrect. SpamFilter does not currently perform additional URL validation before submitting them for DNS lookups, which is why you will see these (innocuous) errors in the logs. 
Performing additional validation before actually checking a URL's domain in DNS would indeed eliminate most of those errors, however validating each URL would add (likely minimal) overhead to the entire process. As most of the times the URLs are actually valid, it was a judgement call on our part as so whether or not to validate URLs that would likely be valid to begin with. We opted not to, but this may change in the future if we see this to become a problem.


-------------
Roberto Franceschetti

http://www.logsat.com" rel="nofollow - LogSat Software

http://www.logsat.com/sfi-spam-filter.asp" rel="nofollow - Spam Filter ISP



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