Does Vista ignore manual MTU settings?

  • Thread starter Thread starter Guest
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G

Guest

Hi, I've installed Vista RC1 64bit & am unable to browse some sites, namely
microsoft sites. In the past this has been due to the MTU & in XP/W2003
Server I set my MTU to 1450 so it passes over the DSL without needing
fragmentation. I use TCPoptimzer or DRtcp to modify the registry. I've done
that for Vista but i still get the wait - Connecting to... then drop to
cannot display webpage.
The PC has an onboard Marvell LAN port (which loads the Vista driver ok) & a
Realtek FE lan card (which loads the vista driver ok). I've tried both
interfaces without luck. I know PMTUD should help but...
Any thoughts appreciated.
Andrew
 
Hello,

Vista does indeed ignore this settings and instead automatically tunes this
value per connection. To disable this feature, follow these steps:

- Click start
- Find command prompt
- Right-click command prompt and click Run As Administrator
- Type: netsh int tcp set global autotuninglevel=disabled
- Press enter
 
I've done this, and used DrTCP (which I ran as Administrator, which was
something I didn't think of at first, causing it not to work!), but I still
can't get to the MS web sites.

I'm having the same trouble as AndrewN - under XP I've set all my PCs to use
an MTU of 1430 and an RWIN of 65535 (or in one obstinate case 111200) and
they're all fine, but when I boot this one into Vista (RC1, 32-bit) I have
the problem I used to have in XP (no access to e.g. www.live.com). I've tried
several different MTU and RWIN settings and used the netsh command you (JB)
mentioned but all to no avail. Any ideas what else I can try?

If this persists there's simply no way I'll be able to upgrade to Vista so
I'll be stuck on XP for ever! :(

Paul
 
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