from small one page howto to huge articles all in one place
 

search text in:





Poll
Which linux distribution do you use?







poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

106243

userrating:

average rating: 1.7 (85 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

220507

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

100907

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





IP\-TCP_METRICS

Section: Linux (8)
Updated: 23 Aug 2012
Index Return to Main Contents
 

NAME

ip-tcp_metrics - management for TCP Metrics  

SYNOPSIS


ip [ OPTIONS ] tcp_metrics { COMMAND | help }


ip tcp_metrics { show | flush } SELECTOR


ip tcp_metrics delete [ address ] ADDRESS


SELECTOR := [ [ address ] PREFIX ]

 

DESCRIPTION

ip tcp_metrics is used to manipulate entries in the kernel that keep TCP information for IPv4 and IPv6 destinations. The entries are created when TCP sockets want to share information for destinations and are stored in a cache keyed by the destination address. The saved information may include values for metrics (initially obtained from routes), recent TSVAL for TIME-WAIT recycling purposes, state for the Fast Open feature, etc. For performance reasons the cache can not grow above configured limit and the older entries are replaced with fresh information, sometimes reclaimed and used for new destinations. The kernel never removes entries, they can be flushed only with this tool.

 

ip tcp_metrics show - show cached entries

address PREFIX (default)
IPv4/IPv6 prefix or address. If no prefix is provided all entries are shown.

The output may contain the following information:

age <S.MMM>sec - time after the entry was created, reset or updated with metrics from sockets. The entry is reset and refreshed on use with metrics from route if the metrics are not updated in last hour. Not all cached values reset the age on update.

cwnd <N> - CWND metric value

fo_cookie <HEX-STRING> - Cookie value received in SYN-ACK to be used by Fast Open for next SYNs

fo_mss <N> - MSS value received in SYN-ACK to be used by Fast Open for next SYNs

fo_syn_drops <N>/<S.MMM>sec ago - Number of drops of initial outgoing Fast Open SYNs with data detected by monitoring the received SYN-ACK after SYN retransmission. The seconds show the time after last SYN drop and together with the drop count can be used to disable Fast Open for some time.

reordering <N> - Reordering metric value

rtt <N>us - RTT metric value

rttvar <N>us - RTTVAR metric value

ssthresh <SSTHRESH> - SSTHRESH metric value

tw_ts <TSVAL>/<SEC>sec ago - recent TSVAL and the seconds after saving it into TIME-WAIT socket

 

ip tcp_metrics delete - delete single entry

address ADDRESS (default)
IPv4/IPv6 address. The address is a required argument.

 

ip tcp_metrics flush - flush entries

This command flushes the entries selected by some criteria.

This command has the same arguments as show.

 

EXAMPLES

ip tcp_metrics show address 192.168.0.0/24

Shows the entries for destinations from subnet

ip tcp_metrics show 192.168.0.0/24

The same but address keyword is optional

ip tcp_metrics

Show all is the default action

ip tcp_metrics delete 192.168.0.1

Removes the entry for 192.168.0.1 from cache.

ip tcp_metrics flush 192.168.0.0/24

Removes entries for destinations from subnet

ip tcp_metrics flush all

Removes all entries from cache

ip -6 tcp_metrics flush all

Removes all IPv6 entries from cache keeping the IPv4 entries.

 

SEE ALSO


ip(8)

 

AUTHOR

Original Manpage by Julian Anastasov <ja@ssi.bg>


 

Index

NAME
SYNOPSIS
DESCRIPTION
ip tcp_metrics show - show cached entries
ip tcp_metrics delete - delete single entry
ip tcp_metrics flush - flush entries
EXAMPLES
SEE ALSO
AUTHOR


Please read "Why adblockers are bad".



Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2017 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 2.8 ms