From owner-freebsd-net  Tue Sep 18  0:58:58 2001
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From: "Matthew Luckie" <kluckie@ihug.co.nz>
To: <net@freebsd.org>
Subject: arp X moved from Y to Z messages
Date: Tue, 18 Sep 2001 19:57:43 +1200
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Hi there

At work there are several freebsd machines that route packets through a
"load balanced" or "redundant" router configuration.
The gateway's IP address actually refers to two different machines.
Naturally the gateway is used quite a bit, and the syslog fills up with "arp
X moved from Y to Z on fxp0" messages.

I'm guessing that not many people would have this problem.
Below is a patch that I have found useful for these machines.
I'm aware that there are security considerations with this patch; by default
the sysctl is not activated.

I'm not subscribed to the list, CC me on any responses please.

Matthew

--- if_ether.c.orig     Tue Sep 18 13:56:16 2001
+++ if_ether.c  Tue Sep 18 14:27:46 2001
@@ -502,6 +502,12 @@
        &log_arp_wrong_iface, 0,
        "log arp packets arriving on the wrong interface");

+static int log_arp_moved = 1;
+
+SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_moved, CTLFLAG_RW,
+          &log_arp_moved, 0,
+          "log arp moved");
+
 static void
 in_arpinput(m)
        struct mbuf *m;
@@ -586,12 +592,13 @@
                }
                if (sdl->sdl_alen &&
                    bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
{
-                       if (rt->rt_expire)
+                       if (rt->rt_expire) {
+                         if(log_arp_moved)
                            log(LOG_INFO, "arp: %s moved from %6D to %6D on
%s%d\n",
                                inet_ntoa(isaddr), (u_char *)LLADDR(sdl),
":",
                                ea->arp_sha, ":",
                                ac->ac_if.if_name, ac->ac_if.if_unit);
-                       else {
+                       } else {
                            log(LOG_ERR,
                                "arp: %6D attempts to modify permanent entry
for %s on %s%d\n",
                                ea->arp_sha, ":", inet_ntoa(isaddr),


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