Re: NAT Negotiation
J C Lawrence <[email protected]>
| Newsgroups | gmane.games.devel.general |
|---|---|
| Message-ID | <[email protected]> |
On Tue, 13 Jan 2004 07:30:58 +0800 Brett Bibby <[email protected]> wrote: > I believe some NATs will increment port numbers and that would be a > good guess to try, but I also read that they may assign random port > numbers. Seems pretty hard to establish a connection to a NAT device > randomly generating port numbers. Hmmm... Every cheap consumer grade low margin NAT box I've examined (roughly a dozen) has used a base algorithm of simply incrementing the last allocated port. Some of them tweak this by periodically/variously stuffing old reclaimed ports back in the available list or some other port recycling pattern, but that's the exception rather than the rule, and a simple retry reduces it to pretty near a 0% margin. Higher end NAT boxes however have all sorts of tricks and behaviours. They allocate seemingly randomly, or with ports as members of a hash function of the address, or some other curiosity, usually in the name of scalability or performance. Some low end boxes do this as well (and no, I can't quote as I'm a long way from home and my files right now), but it isn't common at the lower ends. -- J C Lawrence ---------(*) Satan, oscillate my metallic sonatas. [email protected] He lived as a devil, eh? http://www.kanga.nu/~claw/ Evil is a name of a foeman, as I live. ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html _______________________________________________ Gamedevlists-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gamedevlists-general Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=557