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From: Jim Dennis <jimd@mistery.mcafee.com>
Message-Id: <201006051914.MAA01561@mistery.mcafee.com>
Subject: Re: ifconfig aliasing
To: ptroot@uswest.com (Paul T. Root)
Date: Sat, 5 Jun 110 12:14:48 -0700 (PDT)
Cc: wollman@lcs.mit.edu, questions@freefall.freebsd.org
In-Reply-To: <199606051727.MAA04210@astro.acs.uswest.com> from "Paul T. Root" at Jun 5, 96 12:27:19 pm
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> 
> In a previous message, Garrett Wollman said:
> > <<On Fri, 4 Jun 110 13:59:25 -0700 (PDT), Jim Dennis <jimd@mistery.mcafee.com> said:
> > > 	I tried 'ifconfig ep0:1 alias 205.227.... netmask 255.255...'
> > > 	which the system accepted without error, and which seemed 
> > > 	to add entries into my 'netstat -nr' output.
> That's how sun does address aliasing.
> > This is probably a bug; it should not have accepted `ep0:1'.  What on
> > earth made you decide to write that?

	My previous experience with IP aliasing (very limited) was
	on a Linux box and on a Solaris 2.4.  Both of these also 
	provide the list of aliased interfaces as part of the
	'ifconfig -a' output.

	Someone else on the list provide me with the right answer:

		netstat -i

	(list interfaces)

	Next question:

		Is there a way to collect separate statistics on
		each aliased address?  

	I'd like to monitor the activity on the old address
	so I can drop that interface later.  The whole reason
	we're doing the aliasing is to phase out some addresses
	that are routed through our old T1's and phase them in on the
	router that's fed by our new DS3.  They are from different
	ISP's and we can't carry the adddresses with us (CIDR 
	aggregation limitations).  We aren't running BGP4 and have 
	no intention of doing so (we don't care about dynamic load 
	balancing between our 'homes').

	I'll also be experimenting on some "fail over" scripts
	that allow hosts in my "round robin rings" rings to
	dynamically pick up for one another if one fails temporarily.

Jim Dennis,
System Administrator,
McAfee Associates