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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-04-05 15:47:26 +0000 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-04-05 15:47:26 +0000 |
| commit | b59874b9636df52cf5d330e5bcc0614298af6a31 (patch) | |
| tree | 1275e51583e4e06d3f5a7d34019f56e4eb4f32f6 | |
| parent | 273691af916928cfd033dfc38c468ac0660753c0 (diff) | |
| download | man-pages-b59874b9636df52cf5d330e5bcc0614298af6a31.tar.gz | |
Document IP_PMTUDISC_PROBE, which will be in 2.6.22.
| -rw-r--r-- | man7/ip.7 | 17 |
1 files changed, 17 insertions, 0 deletions
@@ -513,6 +513,7 @@ Path MTU discovery flags:Meaning IP_PMTUDISC_WANT:Use per-route settings. IP_PMTUDISC_DONT:Never do Path MTU Discovery. IP_PMTUDISC_DO:Always do Path MTU Discovery. +IP_PMTUDISC_PROBE:Set DF but ignore Path MTU. .TE When PMTU discovery is enabled the kernel automatically keeps track of @@ -548,6 +549,17 @@ and retrieve the MTU by calling with the .B IP_MTU option. + +It is possible to implement RFC 4821 MTU probing with +.B SOCK_DGRAM +of +.B SOCK_RAW +sockets by setting a value of +.BR IP_PMTUDISC_PROBE . +This is also particularly useful for diagnostic tools such as +.BR tracepath (8) +that wish to deliberately send probe packets larger than +the observed Path MTU. .TP .B IP_MTU Retrieve the current known path MTU of the current socket. @@ -922,6 +934,11 @@ are new options in Linux 2.2. They are also all Linux specific and should not be used in programs intended to be portable. .PP +.\" FIXME +.\" To be confirmed that IP_PMTUDISC_PROBE makes it into kernel 2.6.22 +.I IP_PMTUDISC_PROBE +is new in Linux 2.6.22. +.PP .I struct ip_mreqn is new in Linux 2.2. Linux 2.0 only supported .BR ip_mreq . |