[Asterisk-Users] VOIP Spam

[Duane]

Tom Green wrote:

> Some people have suggested maintaining black lists and
> white lists to avoid spammers and allow legitimate
> callers into the network. However, the problem with
> this method is that the spammer's IP address might
> change due to DHCP. Today a spammer might get
> aaa.bbb.ccc.ddd and lets say that I put this address
> in my blacklist. To my annoyance, tomorrow a
> legitimate caller might get aaa.bbb.ccc.ddd and the
> spammer might get a different IP address. In the end,
> I end up blocking the legitimate caller also. Any
> ideas or thoughts to on this problem is appreciated.

A couple of discussion about this have come up, and something occurred 
to me about the FCC decision about free world dialup not being 
classified as a phone service. This opens the flood gates to 
telemarketers to FWD users as they don't have to honour any form of do 
not call list the FCC issues, which then of course leads on to other 
systems like IAXTEL with all voice data over the internet rather then 
pstn network...

Also a possibly solution may have come out of the same discussions, 
technically if everyone enforces some kind of enum lookup before 
accepting calls, and the same enum lookup will return NAPTR records, so 
a slight modification to loop through all DNS records could then be 
checked against the current hostname/IP in a similar fashion to SPF 
records and mail servers...

End result is a nice neat little database of blacklisted phone numbers 
rather then IPs, you'd need some resolution service/time-out period to 
remove the black listing, but mmmm lot harder to get new phone numbers 
then new IPs...

PS We've come up with a patch to the enum lookup to return a Caller Name 
from a TXT record, appreciate any feedback, our c skills are a little 
rusty so it's possibly not the most elegant solution...

http://bugs.digium.com/bug_view_page.php?bug_id=0001442

-- 
Best regards,
  Duane

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