On 15/07/07 05:48, Andrew Morton wrote:
On Sat, 14 Jul 2007 15:34:31 -0700 (PDT) [EMAIL PROTECTED] wrote:
http://bugzilla.kernel.org/show_bug.cgi?id=8756
It is unclear which kernel version this applies to?
Linus' 2.6 tree, as of Mon Jul 9 15:50:56 2007 -0700
For some reason it says Version: 2.5 on the email and Version: on
the website...
Summary: Route advmss copied to ALL routes when interface MTU
changes
Product: Networking
Version: 2.5
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: IPV6
AssignedTo: [EMAIL PROTECTED]
ReportedBy: [EMAIL PROTECTED]
Steps to reproduce:
1. Have multiple network devices and routes for them with standard (low, i.e.
1500) MTUs and default ADVMSS (e.g. 1440)
2. Change the MTU on one of them to something high (e.g. 7200)
3. The ADVMSS is incorrectly set for ALL routes based on the new MTU of the
interface that changed.
Note: if addrconf is running then the ADVMSS will be reset on the next RA, so
this will impede attempts to reproduce.
# ip -6 r
fe80::/64 dev sit0 metric 256 expires 4481744sec mtu 1480 advmss 1440
hoplimit 4294967295
fe80::/64 dev ppp0 metric 256 expires 19071345sec mtu 1500 advmss 1440
hoplimit 4294967295
fe80::/64 dev eth0 metric 256 expires 19072430sec mtu 1500 advmss 1440
hoplimit 4294967295
default dev ppp0 metric 1024 expires 19071347sec mtu 1500 advmss 1440
hoplimit 4294967295
# ifconfig eth0 mtu 7200
# ip -6 r
fe80::/64 dev sit0 metric 256 expires 4481732sec mtu 1480 advmss 7140
hoplimit 4294967295 -- wrong
fe80::/64 dev ppp0 metric 256 expires 19071334sec mtu 1500 advmss 7140
hoplimit 4294967295 -- wrong
fe80::/64 dev eth0 metric 256 expires 19072419sec mtu 7200 advmss 7140
hoplimit 4294967295 -- correct
Explicitly setting the MTU on these other routes (although this is not
possible
without having to add another route due to bug 8755) automatically sets
ADVMSS
appropriately.
--
Simon Arlott
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