IP alias Networking Errors.

[Grant Peel]

Hello all,

I am running one server that uses a number, (that will grow over time), of
IP aliases.

I am getting a nmber of errors each day that show up in my messages file,
sample:

"May 20 05:55:13 excelsior /kernel: arplookup 216.187.107.97 failed: host is
not on local network"

This machine is using one NIC for all internet traffic and another for local
traffic. The complete setup for the internet NIC looks like this:

fxp0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        inet 65.39.193.154 netmask 0xfffffff0 broadcast 65.39.193.159
        inet 65.39.193.155 netmask 0xffffffff broadcast 65.39.193.155
        inet 65.39.193.156 netmask 0xffffffff broadcast 65.39.193.156
        inet 65.39.193.157 netmask 0xffffffff broadcast 65.39.193.157
        inet 216.187.107.125 netmask 0xffffffff broadcast 216.187.107.125
        inet 216.187.107.126 netmask 0xffffffff broadcast 216.187.107.126
        inet 216.187.107.123 netmask 0xffffffff broadcast 216.187.107.123
        inet 216.187.107.124 netmask 0xffffffff broadcast 216.187.107.124
        ether 00:06:5b:ee:40:32
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

As you can see from above, the original IP was set to 65.39.193.154, and the
subnet set to 0xfffffff0, (255.255.240.0). The IPs (listed above),
65.39.193.155, 65.39.193.156, 65.39.193.157, were assigned to my by my isp
at the same time as the original, and therefore, did not seem to cause any
error messages.

When the next group of IP were assigned to me, and I set them as aliases on
this machine, thats when I started getting the errors. Now, the IP that is
quoted in the error is not a usable IP at all, but rather, happens to be the
'Gateway' IP that was given to me when I got this set of IPs. (When I got
sent the new IPs, I was given a new 'Network Number' and 'Gatweway' number
with those IPs. I did not use them as this machine already has valid Gateway
and Network number in ifconfig.

I should mention that the machine is working fine, and all domains and IPs
are responding great.

SO I suppose my questions are,

Why am I getting this error,
Will it cause any real problems,
and
Should I be making any adjustments?

TIA,

-Grant

Grant W. Peel
Server Admin
grant at thenetnow.com
http://thenetnow.com