Reverse DNS

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Postby Alexander Telegin » Tue Feb 19, 2008 12:51 pm

Oops... that SPF test completely confused me.

Yes, you are right. The DNS tests are not reliable, especially getting PTR record, for reason you have described above, plus some ISP misconfigured and just don't publish PTR zone for dynamic IPs, plus cache at some intermediate DNS server keeping old records. So, I'd not recommend make the final decision the message is spam only because sender IP has not publish PTR record. This theme was discussed many times years ago at mail server forums, but users asked for this option, and it was added to eWall.

Concerning DNSBL or SPF test, I think eWall behave correctly, expecting only specific response and not blocking email if there's a (temporary) DNS failure. Please correct me if I'm wrong.

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Postby dave » Wed Feb 20, 2008 2:34 am

You are 100% correct regarding DNSBL and SPF; eWall is acting perfectly and is providing reliable and safe results for blocking spam, as is SURBL.

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