[cisco-voip] IP Communicator over VPN problem with windows 7 [Solved]

[Ahmed Abd EL-Rahman]

Dear All,

     the problem was solved by the TAC engineer as follows:

 

Problem Cause description:

 

The issue for VPN clients on WIN 7 not being able to connect to IP
communicator could be due to TCP scaling. When ASA receives a packet
greater than 64k then the issue occurs. The workaround is to disable TCP
auto scaling feature on Windows7 but we could also configure ASA to
accept larger size TCP packets.

 

Solving the problem from the ASA:

 

ciscoasa(config)# access-list vpntraffic permit ip <ip address of vpn
client pool> <subnet mask> any

ciscoasa(config)# tcp-map tcpscale

ciscoasa(config-tcp-map)# tcp-options window-scale allow

ciscoasa(config)# class-map tcpwin

ciscoasa(config-cmap)# match access-list vpntraffic

ciscoasa(config)# policy-map global_policy

ciscoasa(config-pmap)# class tcpwin

ciscoasa(config-pmap-c)# set connection advanced-options tcpscale

 

The following is the link for configuring TCP normalization on ASA:

 

http://www.cisco.com/en/US/docs/security/asa/asa82/configuration/guide/c
onns_tcpnorm.html

 

 

Solving the problem from the client PC:

 

On the WIN 7 PC open a command prompt window (cmd) and perform the
following command:

C:\>netsh int tcp set global autotuninglevel=disabled

 

I hope this helps everyone faces this problem.

 

 

 

 

Best Regards

 

Ahmed Abd EL-Rahman I Senior Network Engineer 

CCVP, CCNP, CCNA, CCNA-VOICE, IPTX, UCCX, CRMCS, WLSS

  <http://www.bmbgroup.com/> 

               Lebanon I Egypt I Algeria I KSA I Libya I Jordan


24 x 7 Support Hotline: +966 1 200 5778 | Support Email: 
sa_support at bmbgroup.com

Shahd Investment Center Office #6 I Emam Saud Bin Abdulaziz Rd I Olaya,
Hay al Murooj I P.O Box 17384 I Riyadh, Saudi Arabia I Tel: +966 1
2005813 I Fax: +966 1 2005811 I Mobile: +966 507920925 I 
www.bmbgroup.com <http://www.bmbgroup.com/> 

P     Save a tree. Don't print this e-mail unless it's really necessary

************************************************************
Disclaimer: This email message is for the sole use of the intended
recipient(s) and may contain confidential and privileged information.
Any unauthorized review, use, disclosure or distribution is prohibited.
If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message. 
************************************************************

 

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ahmed Abd
EL-Rahman
Sent: Tuesday, December 28, 2010 5:26 PM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] IP Communicator over VPN problem with windows 7

 

Dear Gents,

                I'm facing a very strange problem with the IP
communicator, it works normally from the LAN using PCs running WIN XP,
Vista, or WIN 7 but when connecting from outside the network using cisco
VPN client it works normally on WIN XP and Vista but not working with
WIN 7 the phone fails to register or sometimes shown on the CM as
registered but in all cases the phone screen remains blank without any
information on it (like the DN or the line text label) and the phone is
not operative (and this is only happens with WIN 7 over the VPN).

And some status errors shown on the phone like the attached photos.

 

So does anyone faced a similar problem ?

 

 

 

Best Regards

 

Ahmed Abd EL-Rahman I Senior Network Engineer 

CCVP, CCNP, CCNA, CCNA-VOICE, IPTX, UCCX, CRMCS, WLSS

 <http://www.bmbgroup.com/> 

               Lebanon I Egypt I Algeria I KSA I Libya I Jordan


24 x 7 Support Hotline: +966 1 200 5778 | Support Email: 
sa_support at bmbgroup.com

Shahd Investment Center Office #6 I Emam Saud Bin Abdulaziz Rd I Olaya,
Hay al Murooj I P.O Box 17384 I Riyadh, Saudi Arabia I Tel: +966 1
2005813 I Fax: +966 1 2005811 I Mobile: +966 507920925 I 
www.bmbgroup.com <http://www.bmbgroup.com/> 

P     Save a tree. Don't print this e-mail unless it's really necessary

************************************************************
Disclaimer: This email message is for the sole use of the intended
recipient(s) and may contain confidential and privileged information.
Any unauthorized review, use, disclosure or distribution is prohibited.
If you are not the intended recipient, please contact the sender by
reply email and destroy all copies of the original message. 
************************************************************

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20110109/dec27fde/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 2384 bytes
Desc: image001.jpg
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20110109/dec27fde/attachment.jpg>