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PPTP VPN MTU

chrisoldinho
Grafter
Posts: 65
Registered: ‎12-04-2010

PPTP VPN MTU

Hi,
Fibre user here, using a different router (RT-N16 with Shibby Tomato custom firmware).
Am running PPTP VPN on my router, currently have the MTU and MRU set at 1450, however I know PPPoE MTU is 1492.
Is 1450 the correct setting? I don't seem to be getting and drops or packet fragmenation, but wondered if there was an "accepted" figure when using Plusnet?
Cheers,
Chris.
2 REPLIES
Community Veteran
Posts: 19,102
Thanks: 443
Fixes: 21
Registered: ‎31-08-2007

Re: PPTP VPN MTU

The normal MTU for PPPoA is 1500 these days, but I haven't a clue if your PPTP VPN has any special requirements other than this link http://support.microsoft.com/kb/826159 suggests 1400 for PPTP VPN. If it doesn't work right - Google is your friend as they say. There is one or two other posters on this board that may know the answer but I don't think they are on-line at the moment.
Community Veteran
Posts: 26,746
Thanks: 959
Fixes: 10
Registered: ‎10-04-2007

Re: PPTP VPN MTU

Experiment! Try
ping -f -l 1450 targetname
where targetname is a server on the VPN.
Vary the 1450 up and down and see if with different VPN settings you can get bigger packets across.
jelv (a.k.a Spoon Whittler)
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