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Date:      Wed, 11 Sep 1996 21:56:54 -0600 (MDT)
From:      Stephen Fisher <>
To:        Jos Vissers <>
Cc:        Bill Fenner <>,,
Subject:   Ethernet routes wrong? [was: Why does arp not work when ip-alias]
Message-ID:  <>
In-Reply-To: <>

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I'm experiencing a similar problem.  My routers and terminal servers and
other servers work fine but FreeBSD just doesn't want to talk to
this one Windows/Dos PC on my ethernet.  What happens is when I try to
ping it it automatically pops up in the routing tables as:

IP.IP.IP.11   link#2             UHRLW       0        7       ep0     10

link#2?  Why?  Then ping start spitting up things about "host is down".

When I manually add it and set the gateteway to someone else on my
ethernet like my main router and it doesn't work out and I delete it the
entire system crashes.

It's weird.. they're all on the same subnet (actually each portmaster's
dialups are on their own subnet).  Everything works thankfully except that
one PC that I need to get working.  I'm not running routed or gated.

Any ideas?

On Thu, 12 Sep 1996, Jos Vissers wrote:

> Bill Fenner wrote:
> > >We have a network with several Livingston portmaster and a
> > >cisco router as gateway. Most of the dial-up ip addresses are on
> > >the same class c network as the servers and therefore arp -a
> > >should give the ethernet address of the portmaster for an
> > >address that is in use.
> > >
> > >It does on machines without an ip-alias.
> > >It doesn't on machines with ip-aliases.
> > 
> > Are machines with IP aliases still able to contact these hosts?
> No, they cannot be reached:
> PING ( 56 data bytes
> ping: sendto: Host is down
> ping: wrote 64 chars, ret=-1
> This is my own machine at home, I could log in to another
> server and then telnet to this one so it should definitely
> have been reacheable. From the dial-up host the server just
> doesn't respond. It apparently knows how to get packets to
> the server, but the server doesn't know how to get them back.
> > What does "netstat -nr" show on the machines with aliases?
> Without routed it shows nothing abnormal until you ping one of
> the dial-up hosts that are connected at the time.
> It wil not show in the routing table and arp -a shows:
> ( at (incomplete)
> If I run routed it shows the portmasters ip as gateway which is correct:
> usquebauch         pm2.nmg            UGH         0        3       ed0
> but arp -a doesn't show any of the dial-up hosts.
> It did some further testing and it only appears to happen
> when I add an ip-alias in another class-c network.
> I used "ifconfig alias netmask 0xffffff00" and
> the machine's regular ip address is
> When I remove the alias again it refuses to start working.
> The problem doesn't occurr when I define aliases in the same
> class-c with - of course - a netmask of 0xffffffff.
> Is this my error? Should I use 2 different ethernet cards
> when using different class-c addresses on one machine?
> Another of our servers with 2 cards doesn't have this problem.
> Thanks for the help, Jos
> -- 
>    Jos Vissers, System administrator Telebyte

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