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Date:      Mon, 10 Aug 1998 20:51:20 +0200 (CEST)
From:      Malte Lance <malte.lance@gmx.net>
To:        steven@shellnet.co.uk (Steven Fletcher)
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: ifconfig difficulties
Message-ID:  <13775.16550.839053.118502@neuron.webmore.de>
In-Reply-To: <35d22bad.6159997@smtp.shellnet.co.uk>
References:  <35d22bad.6159997@smtp.shellnet.co.uk>

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Steven Fletcher writes:
 > Hello all.
 > 
 > I've been using ifconfig for a long time to alias IP addresses to my
 > network card. The command I use is:
 > 
 > ifconfig de0 inet <IP alias address> alias
 > 
 > And then I am able to ping this IP address from any computer on our
 > network and any external computer. However, if the aliased IP is on
 > our first class-c, the same class-c block as the base IP is on, I
 > cannot ping the IP - I recive a "sendto: Host is down" error.
 > 
 > But, if the aliased ip is not on the same class-c as the base ip,
 > pings are successfull.
 > 
 > example:
 > 
 > ifconfig de0 shows:
 > 
 > de0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
 >       inet 194.129.209.11 netmask 0xffffff00 broadcast 194.129.209.255
 >       inet 194.128.147.15 netmask 0xffffff00 broadcast 194.128.147.255
 >       inet 194.129.209.19 netmask 0xffffff00 broadcast 194.129.209.255
 >       ether 00:c0:f0:16:1e:4c
 >       media: autoselect (10baseT/UTP) status: active
 > 
 > I telnet into the box (194.129.209.11 is the base IP) and I am able to
 > ping 194.128.147.15. But if i ping 194.129.209.19, I have no such
 > luck.
 > 
 > Would anyone be able to give the the likley cause of the error or what
 > perhaps I am doing wrong here?

If aliasing host-IP's on ONE network, use a netmask of 0xffffffff for
the alias-command.
>From the beginning of /etc/rc.conf:
...
#ifconfig_lo0_alias0="inet 127.0.0.254 netmask 0xffffffff" # Sample
alias entry.
...

Do you think you could have found it on your own ?

Malte.

 > 
 > TIA,
 > 
 > -Steven Fletcher (steven@shellnet.co.uk)
 > Shellnet - http://www.shellnet.com/
 > 
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