ip-tcp_metrics(8) [v7 man page]
IP-TCP_METRICS(8) Linux IP-TCP_METRICS(8) 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 cre- ated 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> iproute2 23 Aug 2012 IP-TCP_METRICS(8)
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IP-NEIGHBOUR(8) Linux IP-NEIGHBOUR(8) NAME
ip-neighbour - neighbour/arp tables management. SYNOPSIS
ip [ OPTIONS ] neigh { COMMAND | help } ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [ nud { permanent | noarp | stale | reachable } ] | proxy ADDR } [ dev DEV ] ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud STATE ] DESCRIPTION
The ip neigh command manipulates neighbour objects that establish bindings between protocol addresses and link layer addresses for hosts sharing the same link. Neighbour entries are organized into tables. The IPv4 neighbour table is also known by another name - the ARP ta- ble. The corresponding commands display neighbour bindings and their properties, add new neighbour entries and delete old ones. ip neighbour add add a new neighbour entry ip neighbour change change an existing entry ip neighbour replace add a new entry or change an existing one These commands create new neighbour records or update existing ones. to ADDRESS (default) the protocol address of the neighbour. It is either an IPv4 or IPv6 address. dev NAME the interface to which this neighbour is attached. lladdr LLADDRESS the link layer address of the neighbour. LLADDRESS can also be null. nud NUD_STATE the state of the neighbour entry. nud is an abbreviation for 'Neighbour Unreachability Detection'. The state can take one of the following values: permanent the neighbour entry is valid forever and can be only be removed administratively. noarp the neighbour entry is valid. No attempts to validate this entry will be made but it can be removed when its lifetime expires. reachable the neighbour entry is valid until the reachability timeout expires. stale the neighbour entry is valid but suspicious. This option to ip neigh does not change the neighbour state if it was valid and the address is not changed by this command. ip neighbour delete - delete a neighbour entry This command invalidates a neighbour entry. The arguments are the same as with ip neigh add, except that lladdr and nud are ignored. Warning: Attempts to delete or manually change a noarp entry created by the kernel may result in unpredictable behaviour. Particularly, the kernel may try to resolve this address even on a NOARP interface or if the address is multicast or broadcast. ip neighbour show - list neighbour entries This command displays neighbour tables. to ADDRESS (default) the prefix selecting the neighbours to list. dev NAME only list the neighbours attached to this device. proxy list neighbour proxies. unused only list neighbours which are not currently in use. nud NUD_STATE only list neighbour entries in this state. NUD_STATE takes values listed below or the special value all which means all states. This option may occur more than once. If this option is absent, ip lists all entries except for none and noarp. ip neighbour flush - flush neighbour entries This command flushes neighbour tables, selecting entries to flush by some criteria. This command has the same arguments as show. The differences are that it does not run when no arguments are given, and that the default neighbour states to be flushed do not include permanent and noarp. With the -statistics option, the command becomes verbose. It prints out the number of deleted neighbours and the number of rounds made to flush the neighbour table. If the option is given twice, ip neigh flush also dumps all the deleted neighbours. EXAMPLES
ip neighbour Shows the current neighbour table in kernel. ip neigh flush dev eth0 Removes entries in the neighbour table on device eth0. SEE ALSO
ip(8) AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com> iproute2 20 Dec 2011 IP-NEIGHBOUR(8)