Cisco VPN client MTU problem

The concentrators do have a configurable MTU, forceable
fragmentation and
can have the PMTUD turned off. If you haven't had to work
out MTU issues
with VPN then you haven't worked with VPN long enough... 


In my experience, on an Ethernet interface, the Cisco client
sets MTU to
1300.  Sounds like a problem with the install or settings. 
What version of
Cisco client did you install?

Rik

-----Original Message-----
From: nobodygroupstudy.com [mailto:nobodygroupstudy.com] On Behalf
Of
Faryar Zabihi (fzabihi)
Sent: Sunday, April 16, 2006 8:13 AM
To: ciscogroupstudy.com
Subject: RE: Cisco VPN client MTU problem [7:108936]

To add on to my incomplete answer...If the Neoteris works
with larger MTU
size the cisco concentrator should do the same.  So my
previous point might
not be valid in your case...You need to open a TAC case(if u
have access to
them) and get a sniffer trace to see if there is a
negotiation down on the
MTU size... Maybe Juniper isn't doing it? Hard to say. 

 Faryar

-----Original Message-----
From: nobodygroupstudy.com [mailto:nobodygroupstudy.com] On Behalf
Of
Faryar Zabihi (fzabihi)
Sent: Thursday, April 13, 2006 7:22 PM
To: supernet; ciscogroupstudy.com; Cisco certification
Subject: RE: Cisco VPN client MTU problem

Even if you set the MTU size it can still be resized down if
there's a
segment in the communications path that cannot handle the
larger size...
There's a negotiation & notification process in the
communication stream
that helps with that. 


 Faryar 

-----Original Message-----
From: nobodygroupstudy.com [mailto:nobodygroupstudy.com] On Behalf
Of
supernet
Sent: Wednesday, April 12, 2006 10:43 PM
To: ciscogroupstudy.com; 'Cisco certification'
Subject: Cisco VPN client MTU problem

We are comparing Cisco Concentrator and Juniper Neoteris
performance and
noticed that IVE is faster when downloading a same file from
a same server.
Using sniffer I can see Cisco VPN client set packet size to
536 bytes while
Juniper Neoteris set to 1148 bytes. I tried to use VPN
client MTU tool to
set MTU to 1492 or 1300 or 1148 bytes, but sniffer still
shows
536 bytes. I tried to use DrTCP, still no luck. My question
is why I can't
change the packet size? I tried different version of Cisco
VPN client, same
result. Any idea? Thanks. Yoshi

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