From caf5129c82f38f0b2550c1a68f291b12bad472d9 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Fri, 21 Nov 2008 21:41:19 -0500 Subject: [PATCH] arp.7: grfix --- man7/arp.7 | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/man7/arp.7 b/man7/arp.7 index 7f1b9f0d9..bb3117ddb 100644 --- a/man7/arp.7 +++ b/man7/arp.7 @@ -46,7 +46,7 @@ interfaces described below. When there is no positive feedback for an existing mapping after some time (see the .I /proc -interfaces below) a neighbor cache entry is considered stale. +interfaces below), a neighbor cache entry is considered stale. Positive feedback can be gotten from a higher layer; for example from a successful TCP ACK. Other protocols can signal forward progress @@ -54,14 +54,14 @@ using the .B MSG_CONFIRM flag to .BR sendmsg (2). -When there is no forward progress ARP tries to reprobe. +When there is no forward progress, ARP tries to reprobe. It first tries to ask a local arp daemon .B app_solicit times for an updated MAC address. -If that fails and an old MAC address is known an unicast probe is send +If that fails and an old MAC address is known, a unicast probe is sent .B ucast_solicit times. -If that fails too it will broadcast a new ARP +If that fails too, it will broadcast a new ARP request to the network. Requests are only send when there is data queued for sending. @@ -69,7 +69,7 @@ for sending. Linux will automatically add a non-permanent proxy arp entry when it receives a request for an address it forwards to and proxy arp is enabled on the receiving interface. -When there is a reject route for the target no proxy arp entry is added. +When there is a reject route for the target, no proxy arp entry is added. .SS Ioctls Three ioctls are available on all .B AF_INET @@ -92,7 +92,7 @@ struct arpreq { .BR SIOCSARP ", " SIOCDARP " and " SIOCGARP respectively set, delete and get an ARP mapping. -Setting & deleting ARP maps are privileged operations and may +Setting and deleting ARP maps are privileged operations and may only be performed by a process with the .B CAP_NET_ADMIN capability or an effective UID of 0. @@ -143,7 +143,7 @@ Each interface in the system has its own directory in .IR /proc/sys/net/ipv4/neigh/ . The setting in the "default" directory is used for all newly created devices. -Unless otherwise specified time-related interfaces are specified +Unless otherwise specified, time-related interfaces are specified in seconds. .TP .I anycast_delay @@ -178,7 +178,7 @@ Defaults to 30 seconds. .TP .I gc_stale_time Determines how often to check for stale neighbor entries. -When a neighbor entry is considered stale it is resolved again before +When a neighbor entry is considered stale, it is resolved again before sending data to it. Defaults to 60 seconds. .TP @@ -259,7 +259,7 @@ and kernel version-dependent; see .BR time (7). There is no way to signal positive feedback from user space. -This means connection oriented protocols implemented in user space +This means connection-oriented protocols implemented in user space will generate excessive ARP traffic, because ndisc will regularly reprobe the MAC address. The same problem applies for some kernel protocols (e.g., NFS over UDP).