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MFC r273081

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brueffer: New sentence -> new line; use macros where appropriate.

MFC r276345
Mikhail <mp@lenta.ru
Correct naming of sysctl pmtud_blackhole_activated_min_mss.

Clarify some statements around PMTUD blackhole detection to make
the behavior more clear in the man page.
This commit is contained in:
sbruno 2015-08-12 22:51:08 +00:00
parent 3ab328cd1c
commit 3e1f1ceab6
1 changed files with 17 additions and 9 deletions
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26
share/man/man4/tcp.4
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@ -520,23 +520,31 @@ ECN allows a TCP sender to reduce the transmission rate in order to
avoid packet drops.
.It Va ecn.maxretries
Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a
specific connection. This is needed to help with connection establishment
specific connection.
This is needed to help with connection establishment
when a broken firewall is in the network path.
.It Va pmtud_blackhole_detection
Turn on automatic path MTU blackhole detection. In case of retransmits we will
lower the MSS to check if it's MTU problem. If current MSS is greater than
configured value to try, it will be set to it, otherwise, MSS will be set to
default values (net.inet.tcp.mssdflt and net.inet.tcp.v6mssdflt).
Turn on automatic path MTU blackhole detection.
In case of retransmits OS will
lower the MSS to check if it's MTU problem.
If current MSS is greater than
configured value to try, it will be set to configured value, otherwise,
MSS will be set to default values
.Po Va net.inet.tcp.mssdflt
and
.Va net.inet.tcp.v6mssdflt
.Pc .
.It Va pmtud_blackhole_mss
MSS to try for IPv4 if PMTU blackhole detection is turned on.
.It Va v6pmtud_blackhole_mss
MSS to try for IPv6 if PMTU blackhole detection is turned on.
.It Va pmtud_blackhole_activated
Number of times the code was activated to attempt a MSS downshift.
.It Va pmtud_blackhole_min_activated
Number of times the blackhole MSS was used in an attempt to downshift.
Number of times configured values were used in an attempt to downshift.
.It Va pmtud_blackhole_activated_min_mss
Number of times default MSS was used in an attempt to downshift.
.It Va pmtud_blackhole_failed
Number of times that we failed to connect after we downshifted the MSS.
Number of connections for which retransmits continued even after MSS
downshift.
.El
.Sh ERRORS
A socket operation may fail with one of the following errors returned: