Messages in this thread | | | Date | Tue, 14 Dec 2004 17:44:15 +0100 (MET) | From | Jan Engelhardt <> | Subject | Re: bind() udp behavior 2.6.8.1 |
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>sorry "closed" was the wrong term here. We are using a PIX Firewall >Module and it keeps a state table of all connections (tcp and udp). >Thus when a new udp connection comes in with same high numbered source
UDP does not know connections. As such, _nobody_ can tell whether an UDP packet belongs to a logically existing "connection" or not.
>port and the firewall has not removed that connection from its state >table, the firewall drops the packet. The firewall needs about 60ms in >order to clear that connection from the state table, so if a second udp >request with the same high number port/ip comes thru before the firewall >clears the connection from the state table, it will drop the connection >(which is what we are seeing). > >FreeBSD seems to increment future udp requests which prevents this >problem. It just seems strange that the kernel would not randomize or >increment these source ports for udp requests.
The kernel does not have problems with UDP, it's probably your firewall.
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