IP Communicator over VPN problem with windows 7

[ahmed-hassan1110]

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 ?

[reggietuck]

Check your routes in your VPN. It appear that softphone is not

able to load the files. May not be able to reach your CM cluster.

[ahmed-hassan1110]

my dear, ths scenario (VPN) already working with XP and Vista operating systems, the problem only appears with WIN 7, so routing problem is not a reason. furthermore when you are connecting via VPN you can ping the CM and login to the administration page.

[Jonathan Schulenberg]

Assuming the MAC address in CIPC Preferences matches a valid device in CUCM, this strikes me as a firewall issue on the PC. Windows 7 turns on the firewall by default. If not the Microsoft-provided one, perhaps check the anti-malware program on the computer.

Run a packet capture on CUCM and see if the device is registering using the assigned protocol (SIP/SCCP).

[ahmed-hassan1110]

i'm sure that the MAC address is correct, but you may be right regarding the PC firewall. I'll try this and get back to you.

thanks

[paolo bevilacqua]

Which VPN are you using ?

[marahman78]

I am having the same issue and using the latest VPN Client with windows 7 (32 bit), but still the issue remains. Its working fine in LAN but when using vpn client, its not showing soft key template and extension. Working fine in Windows XP with vpn.

[reggietuck]

Also run a capture on the pc as well.

[ahmed-hassan1110]

Dear All,

     the problem was solved by the TAC engineer as follows:

Problem 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 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/conns_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.

[marahman78]

Solve the issue..Thanks

[matthew_mccool]

Thanks for the post. Resolved my issue as well.

[lynn.chase]

The only issue I have experienced is not being able to hear the voicemails when I attempt to check them, and I can hear the people on the in coming calls just fine, but they cant hear me. This is only when I VPN.