12.04 Client Machines Can't Browse Some Websites

[davegravy]

I have my old 10.04 server and a new 12.04 server that I've assembled and am testing (vanilla install, no modifications yet).

I have a win7 client and a win8 client. Both are having intermittent problems accessing certain websites via the new 12.04 core. Specifically, *.tumblr.com (and likely others I just haven't tested thoroughly yet)

• On the win7 machine, Chrome reports ERR_EMPTY_RESPONSE. Several refreshes and the page will usually load. I tried the same pages in IE and they also don't load but IE gives no useful debugging info.
• On the win8 machine, Chrome reports ERR_CONNECTION_RESET for these pages.
• These errors are thrown instantly. There is no time-out.
  
• My android phone can access these sites reliably via Chrome.
• I have no issues with web access on any client with the same configuration through the 10.04 server.

Anyone encountered anything like this or have suggestions to narrow down the issue? I've cleared the browser cache of all my browsers, restarted machines, etc to no avail.

EDIT: Found this which sounds like a similar symptom but I'm not on pppoe so not sure yet how or if this applies https://bbs.archlinux.org/viewtopic.php?id=182527

[davegravy]

10.04 configured my external NIC to MTU 1500

12.04 configured it to 576. I tried changing it to 1500 and haven't yet had the errors reported (they were happening quite frequently before... maybe once in 5 page loads). Will keep an eye on it.

How does the installer decide what to set the MTU to?

[Marie.O]

Probably not a thing setup by the installer, but some new default set by Ubuntu.

[Alblasco1702]

it seams this is not the installer as i don't ave this problem and i stalled my system with a DVD.

[totallymaxed]

Probably not a thing setup by the installer, but some new default set by Ubuntu.

I've have never seen the Ubuntu 12.04LTS Desktop CD installer ever set the MTU that low. I would guess that something else is doing that.

All the best

Andy

[Marie.O]

Maybe some outside DHCP setting happening.

[Dap-P]

MTU 576 is the minimum size for IPv6, maybe that has something to do with it?

I know IPv6 can automatically adjust the MTU size, for an unfragmented end-to-end connection

Anton.