Activate and configure the SIP Application Layer Gateway (SIP ALG) in LANconfig under .
Important: The SIP ALG is disabled in the default settings.
    
    - SIP-ALG activated
 - Activate the SIP Application Layer Gateway here.
 - Ignore rejecting firewall rules for forwarded SIP packets
 - Here you determine whether the firewall for SIP packets respects Reject rules or whether the packets are forwarded by the SIP ALG in any case.