SUMMARY: attach 2 LANS to 1 Physical interface

From: Rich Quinn (
Date: Wed Sep 06 2000 - 19:21:13 CDT


I was cautioned by many about security concerns about doing this.
I didn't mention in my original post that this would have been for a
"practice LAN" that would exist within our LAN.
But the bottom line is that I was told by many that this would not work
with only 1 physical interface.
Thus we will go with physical interfaces.
thanks for the timely replies,

Here is my original Post:


I got a sparc ultra 5 running vers. 8 solaris.
I have it hooked into an HP switch along with the rest of our LAN.
I got the switch configured to have 2 VLAN's(a public and a private).
I have the sparc on both VLANs.

I want to use this sparc as a firewall to the boxes on the private VLAN.
The sparc in question has only one ether interface with 2 logical interfaces.

One interface for each VLAN.

hme0: is on the 198.107 (public) subnet
hme0:1 is on the 10.0 (private) subnet.

I am able to ping boxes on the public subnet, but not the private.

I have Ip forwarding turned on and have removed the /etc/defaultrouter file.

I did a route add net and a route add net through
each logical interface.

Still no luck. Can only ping to the public subnet.

Not sure what is wrong.
Should I NOT be attempting this with only 1 physical interface?
Even though I have it configured to be 2 logical interfaces with different
IP addresses?



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