Messages in this thread |  | | From | "A.N.Kuznetsov" <> | Subject | Re: 2.0.21: TCP hangs solved by disabling Path MTU Discovery | Date | Wed, 25 Sep 1996 18:28:14 +0400 (MSD) |
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Chris Fearnley (cjf@netaxs.COM) wrote: : Greetings,
: I recently reported that HTTP connections were hanging without sending : any data under 2.0.21. Alan Cox's suggestion of building with Path : MTU Discovery disabled has resolved that problem. Thanks Alan, : everything seems to be working fine now. I'll know for sure tonight : when cron runs the tape backup (which also failed under the old kernel).
: The Configure.help listing for Path MTU Discovery suggests it's only : useful for broken PC clients. But many non-local machines including my : PC running 2.0.20 failed to connect to this machine until I rebuilt it : as described. The machine is on a TCP/IP network connected via a Cisco : on a Frame Relay 56k link. Since this is standard technology I'm : uncertain why we ran into the problem. Should Configure.help broaden : it's description of the Path MTU Discovery option or is there still a : bug hiding somewhere?
Apparently, this option should be turned off (and moved to experimental status) by default for 2.0. What a pity! Really, I am sure, if I had at least ONE tcpdump of failed connection, I'd found it. Alas, nobody sent it :-(
Please, try to make it!
- start tcpdump host your-host. Please, do not filter by protocol or destination address. - flush routing cache by adding and deleting any route (route add -host 1.2.3.4 lo; route del 1.2.3.4) - try to make connection, that will fail.
Alexey Kuznetsov.
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