Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Attention: The Community will be in read-only mode on 12/14/2017 from 12:00 am pacific to 11:30 am.

During this time you will only be able to see content. Other interactions such as posting, replying to questions, or marking content as helpful will be disabled for few hours.

We apologize for the inconvenience while we perform important updates to the Community.

New Member

VPN client fixed internet access?

Hi, I have a whole site that can't access many secure sites https. There is nothing that we can see setup to block port 443. The only way around it that I have found is that if the cisco VPN client is installed onto the computer and then uninstalled it seems to fix it. Does anyone know how the installation of the VPN client works that may change the way the PC gets to certain areas. I really want to know why this seems to fix the problem


Re: VPN client fixed internet access?

VPN client do only one thing in this case - it lowers MTU settings of the PC from default 1500 to 1300 value...So it reason why PCs with VPN client can access Internet ...

Some details about MTU

what connection do you use??? Some ADSL lines require MTU between 1430 -1452 I suggest lower MTU for your PCs to 1430...

Here is guide how lower MTU without VPN client installing


Hope that helps rate if it does

New Member

Re: VPN client fixed internet access?


It turned out to be an issue on a router down the line at another site. The MTU was set wrong and your post led me in the right direction thanks for your help.

CreatePlease to create content