Date: Mon, 3 Oct 2016 19:02:22 +0000 (UTC) From: Eric van Gyzen <vangyzen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r306652 - head/usr.sbin/arp Message-ID: <201610031902.u93J2MR8062236@repo.freebsd.org>
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Author: vangyzen Date: Mon Oct 3 19:02:22 2016 New Revision: 306652 URL: https://svnweb.freebsd.org/changeset/base/306652 Log: Update arp(4) to document the net.link.ether.inet.garp_rexmit_count sysctl. Submitted by: David A. Bright <david.a.bright@dell.com> Requested by: markj Reviewed by: markj, badger MFC after: 4 weeks X-MFC with: r306577 Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D8136 Modified: head/usr.sbin/arp/arp.4 Modified: head/usr.sbin/arp/arp.4 ============================================================================== --- head/usr.sbin/arp/arp.4 Mon Oct 3 18:20:58 2016 (r306651) +++ head/usr.sbin/arp/arp.4 Mon Oct 3 19:02:22 2016 (r306652) @@ -28,7 +28,7 @@ .\" @(#)arp4.4 6.5 (Berkeley) 4/18/94 .\" $FreeBSD$ .\" -.Dd November 5, 2013 +.Dd October 3, 2016 .Dt ARP 4 .Os .Sh NAME @@ -126,6 +126,24 @@ the hardware address. Installing such entries is RFC 1812 violation, but some prorietary load balancing techniques require routers on network to do so. Turned off by default. +.It Va garp_rexmit_count +Should the kernel retransmit gratuitous ARP (GARP) packets when an IPv4 address +is added to an interface. +A GARP is always transmitted when an IPv4 address is added to an interface. +A non-zero value of this sysctl will cause the GARP packet to be retransmitted +the stated number of times. +The interval between retransmissions is doubled each time, so the +retransmission intervals are: {1, 2, 4, 8, 16, ...} (seconds). +The default value of zero means only the initial GARP is sent; no +additional GARP packets are retransmitted. +The maximum value is sixteen. +.Pp +Although a single GARP packet (the default behavior) is usually sufficient, in +some circumstances, such as when a shared address is passed between cluster +nodes, this single GARP may be dropped or lost. +This can lead to neighbors on the network link working with a stale ARP cache +and sending packets destined for that address to the node that previously owned +the address, which may not respond. .It Va log_arp_movements Should the kernel log movements of IP addresses from one hardware address to an other.
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