Media hairpinning, 9 media hairpinning – Kerio Tech KERIO WINROUTE FIREWALL 6 User Manual
Page 102
Chapter 7
Traffic Policy
102
Figure 7.39
Definition of a Full cone NAT traffic rule
•
Source — IP address of an SIP telephone in the local network.
•
Destination — name or IP address of an SIP server in the Internet. Full cone NAT will
apply only to connection with this server.
•
Service — SIP service (for an SIP telephone). Full cone NAT will not apply to any other
services.
•
Action — traffic must be allowed.
•
Translation — select a source NAT method (see chapter
) and enable the Allow
returning packets from any host (Full cone NAT) option.
Figure 7.40
Enabling Full cone NAT in the traffic rule
Rule for Full cone NAT must precede the general rule with NAT allowing traffic from the local
network to the Internet.
7.9 Media hairpinning
WinRoute allows to “arrange” traffic between two clients in the LAN which “know each other”
only from behind the firewall’s public IP address. This feature of the firewall is called hairpin-
ning (with the hairpin root suggesting the packet’s “U-turn” back to the local network). Used
especially for transmission of voice or visual data, it is also known as media hairpinning.