Sample setup - simple
In its most simple form, having a SIP profile where your carriers or Internet Telephone Service Providers (ITSPs) reach you versus a SIP profile that your own phones use is inherently beneficial. Most malicious activity starts with someone discovering that you are accepting and responding to SIP traffic on port 5060 via a port scan. At this point they will try various combinations of authentication methods until they find one that works, or otherwise abuse that port. If you restrict access on this IP and change the port to a random number and solely allow inbound calls from carriers using ACLs, you immediately prevent anyone from gaining access to your system, even if they have the right username and password.
The following ...
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