Bastian Schern wrote: > How I can setup Linux to handle UDP fragments?
There's no setting up to do -- it simply handles them correctly. Any IP stack has to. The problem isn't there, but is an unfortunate interaction between the sender and gateway/firewalls along the way. Julio Arruda wrote: | But....it is quite weird they have such a small MTU. Many websites | that have problems with Path MTU discovery would be broken by that | (dumb websites, but still, way too many...). The web sites in question aren't the problem. Again, it's things that happen to the packets along the way that cause communication to fail. The normal scenario is this: A system that wants to do "path MTU discovery" sends out its packets with the "do not fragment" flag set. When a link is reached, along the way to the destination, where the MTU is smaller than the size of the packet, an error message is returned; an ICMP "must fragment" message. The originating system then reduces the size of packets sent to this specific destination -- and, of course, reduces them further if another error is returned. However, lots of firewall "administrators" mistakenly believe that it's a good idea to block ICMP error messages. (They may have heard about abuse of ICMP by black hats back when grandpa was young...) Thus, the error message never gets back to the sender, which keeps sending out too large packets with the "do not fragment" flag, and the packets never reach the destination. Small packets get through, while large ones don't, so a connection can typically be established, but bulk data transfer (ftp data, web pages, &c) doesn't work. Modern Microsoft IP stacks do path MTU discovery by default, which means that the problem is often seen when accessing IIS web sites. But it's not "dumb websites", it's dumb firewall administrators. :-) -tih -- Tom Ivar Helbekkmo, Senior System Administrator, EUnet Norway Hosting www.eunet.no T +47-22092958 M +47-93013940 F +47-22092901 FWD 484145 _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
