Dropped connections with tcp_tw_recycle=1

Michael S. Fischer michael at dynamine.net
Sun Sep 20 22:25:13 CEST 2009

On Sep 20, 2009, at 6:20 AM, Nils Goroll wrote:

>> tcp_tw_recycle is incompatible with NAT on the server side
> ... because it will enforce the verification of TCP time stamps.  
> Unless all
> clients behind a NAT (actually PAD/masquerading) device use  
> identical timestamps
> (within a certain range), most of them will send invalid TCP  
> timestamps so SYNs
> will get dropped.

Since you seem pretty knowledgeable on the subject, can you please  
explain the difference between tcp_tw_reuse and tcp_tw_recycle?



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