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AGFox
Posts: 45
Registered: ‎05-17-2011

Suggestions to prevent lost VPN client connections

[ Edited ]

Dropped VPN connections

 

I experienced a similar issue a few years ago with my LinkSys WRT54G router with dropped connections to my corporate network using the Cisco VPN Client.  To make a long story short the problem was the result of the following:

 

   1. The default ""Client Lease Time" on LinkSys routers is 0 which means 1 day or 24 hours.

   2. By DHCP Protocol definition, DHCP clients must renew the DHCP client IP address lease at the 1/2 life cycle

         of  the lease (12 hours if using the router's default setting).  This is deadly for VPN clients as the short period

         of time when the client IP address is no longer valid, the VPN client considers this a loss of network connection. 

         The LinkSys E-series routers further aggravate the situation by randomly assigning new IP addresses to

         DHCP clients instead of reassigning the client's previous IP address and tends to favor higher host IP addresses

         in the defined range.

 

Suggestions to prevent lost VPN client connections:

 

   1. Change the "Client Lease Time" on the router to 8640 minutes (6 days 00:00:00).
   2. Prior to establishing a VPN client connection, use the Windows Command Prompt to issue the "ipconfig /renew"

         command to obtain a new IP address from the router that will be good for 3 days (72 hours).
   3. Configure your E-series router to use the <DHCP Reservation> option to pre-assign IP addresses to your systems

        making sure they are outside the range of the dynamically assigned DHCP addresses.  Using default settings,

        these would be in the range of 192.168.1.2 thru 192.168.1.99 as the router starts at 192.168.1.100 thru

       192.168.1.149.  This will guarantee you system will get the same IP address at all renewals.

 

(Mod note: Thank you for the suggestion. We made this a sticky for other users to see. Kudos to you!)

newfrad
Posts: 4
Registered: ‎12-26-2011

Re: Suggestions to prevent lost VPN client connections

VPN is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network.

Advantages

  • Allows you to be at home and access your company's computers in the same way as if you were sitting at work.
  • Almost impossible for someone to tap or interfer with data in the VPN tunnel.
  • If you have VPN client software on a laptop, you can connect to your company from anywhere in the world.

VPNs may serve any network functionality that is found on any network, such as sharing of data and access to network resources, printers, databases, websites, etc.

 

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