2.0.21: TCP hangs solved by disabling Path MTU Discovery

Chris Fearnley (cjf@netaxs.com)
Tue, 24 Sep 1996 16:45:42 -0400 (EDT)


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?

Christopher J. Fearnley            |    Linux/Internet Consulting
cjf@netaxs.com, cjf@onit.net       |    UNIX SIG Leader at PACS
http://www.netaxs.com/~cjf         |    (Philadelphia Area Computer Society)
ftp://ftp.netaxs.com/people/cjf    |    Design Science Revolutionary
"Dare to be Naive" -- Bucky Fuller |    Explorer in Universe