amd64/148537: IP respond to ping even if the attached interface is no carrier

[Vlad Galu]

The following reply was made to PR amd64/148537; it has been noted by GNATS.

From: Vlad Galu <dudu at dudu.ro>
To: Fabrice Bruel <fabrice.bruel at orange-ftgroup.com>
Cc: freebsd-gnats-submit at freebsd.org
Subject: Re: amd64/148537: IP respond to ping even if the attached interface 
	is no carrier
Date: Tue, 13 Jul 2010 13:26:02 +0200

 On Tue, Jul 13, 2010 at 10:52 AM, Fabrice Bruel
 <fabrice.bruel at orange-ftgroup.com> wrote:
 >
 >>Number: =A0 =A0 =A0 =A0 148537
 >>Category: =A0 =A0 =A0 amd64
 >>Synopsis: =A0 =A0 =A0 IP respond to ping even if the attached interface i=
 s no carrier
 >>Confidential: =A0 no
 >>Severity: =A0 =A0 =A0 serious
 >>Priority: =A0 =A0 =A0 medium
 >>Responsible: =A0 =A0freebsd-amd64
 >>State: =A0 =A0 =A0 =A0 =A0open
 >>Quarter:
 >>Keywords:
 >>Date-Required:
 >>Class: =A0 =A0 =A0 =A0 =A0sw-bug
 >>Submitter-Id: =A0 current-users
 >>Arrival-Date: =A0 Tue Jul 13 09:10:02 UTC 2010
 >>Closed-Date:
 >>Last-Modified:
 >>Originator: =A0 =A0 Fabrice Bruel
 >>Release: =A0 =A0 =A0 =A0FreeBSD 8.0 release amd 64
 >>Organization:
 > OBS
 >>Environment:
 > FreeBSD HPFBSD8PF64 8.0-RELEASE-p3 FreeBSD 8.0-RELEASE-p3 #0: Fri Jul =A0=
 9 08:47:02 GMT 2010 =A0 =A0 root at HPFBSD8PF64:/usr/obj/usr/src/sys/FBSD8PF =
 =A0amd64
 >
 >>Description:
 > Hello,
 >
 > Please considered a server with two or more physicals Ethernet Interfaces=
 . To supervise this server, we are using a tool that try to ping all the IP=
  address of the server, but the IP packet come by just one interface (that =
 is on the same LAN on the supervision tool).
 >
 > If an interface is "no carrier", its IP answer very well to the ping requ=
 est, so in our tool, everything seems to be OK.
 >
 > Is it possible that the FreeBSD Kernel checks the status of an interface =
 before answer ?
 >
 > Thanks
 > Fabrice
 >>How-To-Repeat:
 > - A server with two physical interfaces.
 > - a static route to access the second interface through the first interfa=
 ce
 > - unplugged the network cable in the second interface
 > - ping @IP_attached_to_the_second_interface
 >>Fix:
 >
 >
 >>Release-Note:
 >>Audit-Trail:
 >>Unformatted:
 > _______________________________________________
 > freebsd-amd64 at freebsd.org mailing list
 > http://lists.freebsd.org/mailman/listinfo/freebsd-amd64
 > To unsubscribe, send any mail to "freebsd-amd64-unsubscribe at freebsd.org"
 >
 
 What you describe here is not a bug, but really a feature - IP
 forwarding. IP addresses aren't bound to interfaces by link states,
 but by configuration. What you can do is add a route to another IP
 address directly connected to the interface that flaps, and ping that
 address instead.
 
 
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