[PLUG] OT: VoiceSpamAssassin

John Todd jtodd at loligo.com
Fri Jun 27 10:01:01 UTC 2003


>The federal government has opened its national Do-Not-Call registry:
>
>* http://donotcall.gov (I couldn't get through this morning)
>* (888) 382-1222
>
>c|net has a write up:
>
>   http://news.com.com/2100-1037_3-1021645.html?tag=fd_top
>
>--Paul Heinlein <heinlein at attbi.com>

A better solution to phone spam is Asterisk, with it's included 
Zapateller and PrivacyManager modules.

Short description: Asterisk (http://www.asterisk.org/) is an OSS PBX 
system which can be easily turned into a voicemail and VoIP gateway 
for your house.  With the addition of a $100 card, it can take your 
house line into the back of your Linux box and pre-parse your calls. 
Then, upon completion of checking your calls, it will forward the 
call to either a SIP device (like a Cisco ATA-186, with two lines at 
~$130) or to any other gateway of your choice.

If your caller does not have caller ID, the Zapateller application 
plays the first three tones of a "number out of order" recording, 
which most automated phone bots will take as a "bad number" and they 
will remove you from their database and hang up at the same time. 
This gets about 50% of the phone spam that I see.

The PrivacyManager application next looks for any inbound calls 
without caller ID.  It forces the caller to enter in a valid caller 
ID through the touch-tone pad.  Most telemarketers will not do this 
(none, actually, in my experience) and they hang up.  Since 
implementing Asterisk, I have had two spam calls get through (six 
months.)

You can get more sophisticated than that if you want: blacklists, 
whitelists, pre-announcements on _all_ calls, database lookups.  It's 
all possible.

JT




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