Re: I'm missing 2 bytes (GRE implementation)

2011-08-10 Thread William Herrin
On Wed, Aug 10, 2011 at 12:36 PM, Daniel Roesen wrote: > On Wed, Aug 10, 2011 at 12:57:44AM +, Franck Martin wrote: >> I'm using a GRE IPv4 tunnel between a cisco and linux machines >> So why Cisco is off by 2 Bytes? > > The only GRE options using 2 bytes are GRE checksum and offset. Haven't >

Re: I'm missing 2 bytes (GRE implementation)

2011-08-10 Thread Daniel Roesen
On Wed, Aug 10, 2011 at 12:57:44AM +, Franck Martin wrote: > I'm using a GRE IPv4 tunnel between a cisco and linux machines Can you mail: IOS: - sh run int TuX - sh int TuX | i MTU - sh ip int TuX | i MTU Linux: - output of "/sbin/ip link show greX" (or whatever your GRE interface is named

Re: I'm missing 2 bytes (GRE implementation)

2011-08-09 Thread Stefan Fouant
. - Reply message - From: "Franck Martin" Date: Tue, Aug 9, 2011 5:57 pm Subject: I'm missing 2 bytes (GRE implementation) To: "nanog@nanog.org" I'm using a GRE IPv4 tunnel between a cisco and linux machines I did some packet capture, and saw that my MTU was 1418,

I'm missing 2 bytes (GRE implementation)

2011-08-09 Thread Franck Martin
I'm using a GRE IPv4 tunnel between a cisco and linux machines I did some packet capture, and saw that my MTU was 1418, but the cisco was sending TCP packet with a MSS of 1380. This created a bunch of issues. When I told the cisco box to use a MSS of 1378 everything starting to work fine. So wh