Discussion in 'Networking Issues' started by glock918, May 12, 2006.

  1. glock918

    glock918 Network Guru Member

    I have a WRV54G (firmware version 2.37) at home. I’m using Comcast as my ISP, the modem is Linksys BEFCMU10. I’m using DYNDNS.com for my “static†IP address solution. All computers involved are XP PRO, SP2.

    I loaded Quick VPN on the remote computer following the excellent instructions I found here. It connects; I get the little green icon. On the router I connect to (the home WRV54G) it says I connected. Linksys manual says to ping a remote computer to test it out, so I pined the local IP of the remote computer, and I got request timed out.

    Here is what I’m after. I will be away from home and I need a secure connection to conduct business. I figure the best way is to VPN to home (that I sure of as far as is viruses and spyware free) and then go to the net.

    How do I test and set up this VPN?

    Thanks in advance.

    Art in KY
  2. DocLarge

    DocLarge Super Moderator Staff Member Member

    First thing you need to do is make sure you have no firewall up on the computers you want to access.

    Second, you need to check the MTU of your internet connection and make sure the packets aren't too large for transmission. Here's the formula:

    ping -f -l [mtu] [gateway] Here's an example:

    ping -f -l 1492

    "Gateway" is provided by your isp, by the way...

    What we're doing is finding out what is the best mtu size for your internet connection. If you get a response like the following below, your mtu size is alright:

    C:\>ping -f -l 1400 87.xxx.xxx.xxx

    Pinging 87.xxx.xxx.xxx with 1400 bytes of data:

    Reply from 87.xxx.xxx.xxx: bytes=1400 time<10ms TTL=255
    Reply from 87.xxx.xxx.xxx: bytes=1400 time<10ms TTL=255
    Reply from 87.xxx.xxx.xxx: bytes=1400 time=10ms TTL=255
    Reply from 87.xxx.xxx.xxx: bytes=1400 time<10ms TTL=255

    I ran this test on my connection. In actuality I can go all the way up 1470 before it says my packets are too large. This is what you'll see in that instance:

    Packet needs to be fragmented but DF set.

    Run the test starting at 1490 and work your way backwards in increments of "50" (i.e., 1490, 1485, 1480, etc..). You can then set the mtu one of two ways:

    1) Set the mtu on the wrv to "manual" and then change it to the mtu size you find

    2) Download Dr TCP and instantaneously set the registry size on your computer to the mtu size you find

    In the first instance, you're setting the size for your entire network (the router will handle it regardless of the defaults of "1500" on your computer) whereas the second example, the computer is directly responsible for establishing the proper mtu size.

    Also, upgrade your firmware if possible. 2.37 is BAD. Try 2.37.13 or 2.39.

    For furture questions regarding your WRV54G, post in this forum:


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