[76786] in North American Network Operators' Group
Smallest Transit MTU
daemon@ATHENA.MIT.EDU (Jerry Pasker)
Wed Dec 29 13:31:17 2004
Date: Wed, 29 Dec 2004 12:30:04 -0600
To: nanog@merit.edu
From: Jerry Pasker <info@n-connect.net>
Errors-To: owner-nanog-outgoing@merit.edu
Operational comment, question:
I've learned that having an MTU smaller than 1500 bytes is a bad
thing. When encountering networks with MTUs smaller than 1500 bytes,
path MTU discovery breaks when sites like a computer science college
my friend is going to .edu, a certain 'us' online bank.com, and the
worlds most popular auction site.com block all icmp, including the
icmp "fragmentation needed but DF bit set" packets. Despite what
the RFCs say, the transit internet, in my opinion, generally needs to
accept and transit packets up to 1500 bytes without packet
fragmentation.
Is this consistent with what everyone else's operational experiences?
Is there an RFC that clearly states: "The internet needs to transit
1500 byte packets without fragmentation."??
