17 lines
876 B
Plaintext
17 lines
876 B
Plaintext
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tcpmssd was written by Ruslan Ermilov <ru@FreeBSD.org> based on work
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done by Patrick Bihan-Faou <patrick@mindstep.com>.
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tcpmssd is a divert(4) program that adjusts outgoing TCP data so that
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the requested segment size is not greater than the amount allowed by
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the interface MTU.
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This is necessary in many setups to avoid problems caused by routers
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that drop ICMP Datagram Too Big messages. Without these messages,
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the originating machine sends data, it passes the rogue router then
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hits a machine that has an MTU that is not big enough for the data.
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Because the IP Don't Fragment option is set, this machine sends an
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ICMP Datagram Too Big message back to the originator and drops the
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packet. The rogue router drops the ICMP message and the originator
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never gets to discover that it must reduce the fragment size or drop
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the IP Don't Fragment option from its outgoing data.
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