Anonymous/Unsolicited Calls Protection; Figure 11: Settings To Block Anonymous Call; Figure 12: Settings To Block Unwanted Calls - Grandstream Networks GAC2500 Security Manual

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Local RTP port:
The default port value is 5004. The Local RTP port can be configured from web UI → Advanced Settings
→ General Settings. This parameter defines the local RTP-RTCP port pair used to listen and transmit.
If it is configured with X, in channel 0 the port X will be used for audio RTP message, the port X+1 for
audio RTCP message, the port X+2 for video RTP message and the port X+3 for video RTCP. In
Channel 1, each port number will be incremented by 4 for each message. This increment rule will apply
to other channels and other port numbers. By default, the Account 1 will use Channel 0, Account 2
Channel 1, Account 3 Channel 2, Account 4 Channel 3, and Account 5 Channel 4 and Account 6
Channel 5. If an account needs to establish multiple session simultaneously, the system will use the
ports in the next available channels. The valid range is from 1024 to 65400.

Anonymous/Unsolicited Calls Protection

If the user would like to have anonymous calls blocked, please go to GAC2500 web UI → Account →
Account x → Call Settings and enable option "Reject Anonymous call". This will automatically block the SIP
call if the caller ID is anonymous.
Additionally, the GAC2500 has built-in mechanism that detects and stops the spam SIP calls from ringing
the phones. Please see below web UI → Account → Account x → Advanced Settings. It is recommended
to enable highlighted options to validate incoming SIP requests.
Figure 10: Settings to Block Anonymous Call
Figure 11: Settings to Block Unwanted Calls
GAC2500 Security Guide
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