Showing results for 
Search instead for 
Did you mean: 

help. 2048 sized pings failing over ipsec tunnel

Chris Knipe

So because of the way active directory handles Group Policy I have been tasked with finding out why this is failing over the WAN.  Basically I know why, but don't know how to correct it.  I am trying to increase the MTU over an ipsec tunnel to 2048 to allow Microsoft Slowlink detection to occur. .  Basically, it sends 2 icmp packets.  One at a normal size and one at a size of 2048. In my case this is trying to occur over an ipsec tunnel and failing due to the MTU being at 1440.  I have seen a few articles about increasing it to 1500, but is there a way to increase the MTU to allow the 2048 sized icmp packets?


paolo bevilacqua
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

No, there is no way.

You can't fit a size 9 foot in a size 6 shoe.

Is it not possible to just increase the MTU on the tunnel on both sides to 2048?  I am getting the idea from this, that the maximum is 1500

I have answered to you above already.

You can then do your experimenting, then report here the results.

thanks for clarifying /s

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: