Changes between Initial Version and Version 1 of NAT_Routers_Issues


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Timestamp:
Nov 12, 2008 11:40:25 AM (16 years ago)
Author:
bennylp
Comment:

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  • NAT_Routers_Issues

    v1 v1  
     1= Issues with NAT/Routers = 
     2 
     3Lets use this page to document peculiar things that NAT/routers do when it comes to processing SIP/STUN messages. 
     4 
     5== Behavior Classification == 
     6=== Inspection and Modification of SIP/SDP Messages === 
     7 
     8Some routers inspect and modify SIP/SDP message content in its naive attempt to assist NAT traversal. Parts of the SIP/SDP message elements that the router modifies include the Via and Contact header, and SDP c= and m= lines. Some router even goes further with doing what seems to be simple text search/replace, replacing all occurrences of private IP address/port in SIP/SDP message with the public IP address/port. 
     9 
     10This behavior may break ICE offer/answer negotiation. If the router replaces the default candidate with IP address/port which is not listed in the candidate list in SDP, remote callee will reject ICE offer with ice-mismatch, and ICE negotiation will not take place. 
     11 
     12 
     13== Known Router Brands == 
     14 
     15=== Belkin Wireless ADSL Router === 
     16 
     17|| Reported in: || UK || 
     18|| Version: || Firmware: 6.01.06 (Jun 7 2006 20:25:29), boot version: 0.70.2v6, hardware: 01 || 
     19 
     20 '''Inspects and modifies SIP/SDP messages''':: 
     21 This router inspects and modifies SIP/SDP messages if the outer address is port 5060. 
     22