<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On 28 Feb 2011, at 10:33, Rizwan Hisham wrote:</div><blockquote type="cite">The problem I have been experiencing since last month is that some of my customers are getting calls with "Asterisk <Unknown>" caller id. Most of them in the middle of the night. And my asterisk server has no record of these calls. The customers were getting irritated as you can imagine. I guessed the only way to receive incoming calls by by-passing the registration server is thru sip-uri calls directly to customers. I have updated the customers atas to not accept any calls from sources other than the registration server. Thats all fine now. But the question is how can anyone know the direct sip uri addresses of our customers.<font class="Apple-style-span" color="#000000"><font class="Apple-style-span" color="#144FAE"><br></font></font></blockquote><div><br></div>'asterisk security' is a misleading subject line. Guessing someone just scanned some IP addresses and made calls. You need what's called a 'firewall'.</div><div><br><blockquote type="cite">My guess is that someone has been sniffing my server's sip traffic. In that case what should i do to get rid of the sniffers?<br></blockquote><div><br></div><div>It's hard to sniff without being on a network. Most likely they brute forced something?.. Get a firewall, and something to look for brute force attacks.</div></div><br><div>S</div></body></html>