wrong mtu value in /proc/net/route

wrong mtu value in /proc/net/route

[Bruce Cran]

I've found something strange going on in 2.4 kernels - when I run
'netstat -r' I get the routing table from /proc/net/route.   The MSS
value reported is only 40 bytes, and when I run 'cat
/proc/net/route I'm told that the _MTU_ is 40 bytes.   I thought the MSS was
supposed to be the MTU - 40 bytes, not 40 bytes in
total, where the MTU for ethernet is 1500.  If I run ifconfig, it reports the 
correct MTU of 1500 for eth0 and 16463 for lo.   This computer has a NetGear 
FA311 card, and is running 2.4.19-pre7-ac2, though I've also seen this 
happening on a 2.4.18 kernel.

--

Bruce Cran

Re: wrong mtu value in /proc/net/route

[Rudmer van Dijk]

On Thursday 25 July 2002 23:34, Bruce Cran wrote:
> I've found something strange going on in 2.4 kernels - when I run
> 'netstat -r' I get the routing table from /proc/net/route.   The MSS
> value reported is only 40 bytes, and when I run 'cat
> /proc/net/route I'm told that the _MTU_ is 40 bytes.   I thought the MSS
> was supposed to be the MTU - 40 bytes, not 40 bytes in
> total, where the MTU for ethernet is 1500.  If I run ifconfig, it reports
> the correct MTU of 1500 for eth0 and 16463 for lo.   This computer has a
> NetGear FA311 card, and is running 2.4.19-pre7-ac2, though I've also seen
> this happening on a 2.4.18 kernel.

I see the same values on 2.4.19-rc3-ac3 with two Winbond Electronics Corp 
W89C940 NIC's. no idea what is causing it.

	Rudmer

Re: wrong mtu value in /proc/net/route

[Athanasius]

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On Fri, Jul 26, 2002 at 12:14:30AM +0200, Rudmer van Dijk wrote:
> On Thursday 25 July 2002 23:34, Bruce Cran wrote:
> > I've found something strange going on in 2.4 kernels - when I run
> > 'netstat -r' I get the routing table from /proc/net/route.   The MSS
> > value reported is only 40 bytes, and when I run 'cat
> > /proc/net/route I'm told that the _MTU_ is 40 bytes.   I thought the MSS
[snip]
> 
> I see the same values on 2.4.19-rc3-ac3 with two Winbond Electronics Corp 
> W89C940 NIC's. no idea what is causing it.

  Same here with:

Kernel 2.4.18-pre8
eth0: NE2000 found at 0x240, using IRQ 10.
eth1: 3c5x9 at 0x320, 10baseT port, address  00 60 97 ad 3f 84, IRQ 5.
eth2: RealTek RTL8139 Fast Ethernet at 0xd8855000, 00:50:bf:ea:0f:41, IRQ 9

Kernel 2.4.18
Ethernet controller: 3Com Corporation 3c905C-TX [Fast Etherlink]

Kernel 2.4.19-rc1
eth0: RealTek RTL8139 Fast Ethernet at 0xe0863f00, 00:20:ed:1d:fe:2a, IRQ 5

  Again, ifconfig on both machines shows the correct values.

  I've not gotten around to trying 2.4.19-rc3 yet.

-Ath
-- 
- Athanasius = Athanasius(at)miggy.org.uk / http://www.clan-lovely.org/~athan/
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	   "And it's me who is my enemy. Me who beats me up.
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