Iljitsch van Beijnum
iljitsch at muada.com
Mon Aug 25 05:56:34 CDT 2008
On 25 aug 2008, at 12:27, Fernando Gont wrote:
> IPv4 minimum MTU is 68 bytes,
That's kind of like "a human being can live without food for four to
six weeks". It's not a recommendation.
> 536 is the minimum fragment re-assembly buffer size. Falling back to
> 536-byte packets does not guarantee that sessions will be kept up.
"PMTU black hole router detection is triggered on a TCP connection
when TCP starts retransmitting full-sized segments with the DF flag
set. TCP resets the PTMU for the connection to 536 bytes. Then, TCP
retransmits its segments when the DF flag is clear."
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