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MSS Initiative Makes Progress
Phil writes "The MSS Initiative was started by Richard van den Berg and myself to combat sites that are broken (enable Path MTU Discovery AND block ICMP 3,4) which include such big sites as SecurityFocus and CERT (causing those behind PPPoE and other less-than-1500-MTU-protocols to be unable to view the sites). This past week we were priveleged enough to be able to present a paper at the 16th LISA Systems Administration Conference! Check out the paper and slides and be sure, like many members of the audience, to fix the sites you administer!"
The PDF of the paper refuses to render with any Ghostscript derived viewer.
It sure would be nice if those who wish to cast stones would make sure their own position is clean.
That said, I've had to ding webmasters about having their routers set up to block packets with explicit congestion notify set - that is now an accepted part of TCP/IP, and failing to accept packets with ECN set is a violation of the standard.
www.eFax.com are spammers
MTU has turned into the bane of my existence, between atm header problems, VPN's which can't have their packets fragmented without blowing up their crc's, and voice and video apps over low speed links adjusting the MTU down isn't an option anymore, many times it is required. Maybe a site here or there won't display, but usually its downloads that die, like a norton update for example. If I reset the mtu back to 1500 then the vpn's drop and voice develops jitter or drops (using a vovpn as an example)but everyone can download their updates (and of course more importantly their mp3's.) My point is that allowing your ftp server to service a packet at 750 won't kill you or your server. How much overhead do you add by sending two packets at 750 over one at 1500 and how much bandwidth will you save? Until this problem completely disappears I will keep a copy of DR. TCP on my laptops, I believe you can free copies of it from Cisco (might need to be registered)