From: Guyler, Rik (rguyler@shp-dayton.org)
Date: Mon Jun 25 2007 - 12:56:21 ART
The Linux part of your post makes sense to me. I was having some issues
with our first VPN site that used the 1800-series routers instead of the
3002. As expected, with no MTU tweaking, web content was really struggling
from the client hosts at the site. When I moved the TCP MSS down to 1400,
the PCs happily accepted the change and began humming right along but the
MACs (running OS 10.x, a Linux-based OS) there would not cooperate no matter
what I did with the MSS value. I finally had to change the MTU on each MAC
to 1400 to get them to work properly.
As for AOL, maybe they are sending out smaller packets to begin with?
Rik
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
johngibson1541@yahoo.com
Sent: Saturday, June 23, 2007 9:32 AM
To: ccielab@groupstudy.com
Subject: Such thing as malpractice administrator blocking ICMP and expecting
path mtu discovery ?
They have a list of sites blocking ICMP
and web users can only do path mtu discovery to do the right thing.
http://www.netheaven.com/pmtulist.html
among which aol.com is one of those.
Is that page legitimate? How could there be such a big problem in aol.com
when millions are happily using it?
If they have "tcp adjust-mss" at their router for tcp connections, web users
will be fine.
Only issue will be aol.com's own admins that use SNMP (UDP).
Maybe the page's author doesn't know about "tcp adjust-mss"?
I use wireshark to monitor my own packets to download http pages (almost all
pages today in mail.yahoo or are bigger than 1500).
I have never seen my Linux PC sending out any path MTU discovery.
My PC's default mss is 1460.
I still believe Linux (mine is fedora) does not have TCP ECN by default.
John
This archive was generated by hypermail 2.1.4 : Sun Jul 01 2007 - 17:24:51 ART