RE: Very Strange Problem

Your dialer MTU should be no higher than 1492. Right now it is at the
default of 1500.

Try changing the MTU on the host itself to 1300 or something. I changed my
MTU on my laptop to 1350 to solve problems when windowing was being ignored
by servers.

To do it on a windows machine follow these instructions

http://smallvoid.com/article/vista-tcpip-mtu.html

See if that solves the problem

Regards,
 
Tyson Scott - CCIE #13513 R&S, Security, and SP
Managing Partner / Sr. Instructor - IPexpert, Inc.
Mailto: tscott_at_ipexpert.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Sidney Spencer
Sent: Thursday, July 01, 2010 11:02 PM
To: Cisco certification
Subject: Very Strange Problem

Hello all,

 I have run into an issue that I am having the hardest time trying to figure
out what it is. Here is what is happening:

I have a 2801 Router with and ASDL wic installed in it. There is currently
3 site to site VPN's configured, and basic routing, and PAT. What is
happening is every time a user behind this router tries to access the
internet (going to a site www.yahoo.com or facebook etc) it basically sits
there and just continues to load and take forever but never comes up, if I
go to www.google.com that has no images to load it comes up really quick
with no issue. Here is a kicker, if I try to load a web page on internal
site on the other side of the tunnel everything comes up as normal with no
problems, the issue is only when I try to access external websites from that
location. I am able to ping and telnet to port 80 with no problems. I
thought it was a fragmentation issue, so I changed MTU and MSS as low as
1200 and the problem still persists. Has anyone else seen this issue? I
found the issue on the internet but have not seen where anyone has come up
with a fix for it, so I thought I would see if anyone here may have seen
this issue and resolved?

The configuration is pretty basic (snippits)

F0/0 - Shutdown
!
interface FastEthernet0/1
 description $ES_LAN$
 ip address 192.168.90.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 duplex auto
 speed auto

interface ATM0/3/0
 no ip address
 no ip mroute-cache
 no atm ilmi-keepalive
 dsl operating-mode auto
 hold-queue 224 in
!
interface ATM0/3/0.1 point-to-point
 pvc 8/32
  encapsulation aal5snap
  pppoe-client dial-pool-number 1
 !
!
interface Dialer1
 ip address negotiated
 ip nat outside
 ip virtual-reassembly
 encapsulation ppp
 dialer pool 1
 dialer-group 1
 no cdp enable
 ppp authentication chap pap callin
 ppp chap hostname xxxxxxxxx
 ppp chap password 0 xxxxxxxx
 ppp pap sent-username xxxxxxxxxx password 0 xxxxxxxxx

ip route 0.0.0.0 0.0.0.0 Dialer1

ip nat inside source route-map internet_nat interface Dialer1 overload

ADSL is used because that is the only option in the location in which this
router is located. Any ideas on where I should be looking is much
appreciated, the next step for me is to probably open a TAC case but wanted
to get others thoughts first..

Sid

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Received on Thu Jul 01 2010 - 23:14:30 ART