Problem with ip-alias and internet

[Peter Ulrich Kruppa]

Hi!

Some days ago a strange problem involving our samba server, our
squid proxy and some subnets occured.
This is the network design:

                     internet
                        |
                    DSL-ROUTER
                   172.16.1.254    +---other subnets
                        |          |
     172.16.1.0------switch--------+
       subnet        |   |         +---172.16.11.0
                     |   +------+      subnet
                   SAMBA      SQUID
                  server      proxy
               IP-aliases:    172.16.2.249
               172.16.1.1
               172.16.2.1
               172.16.11.1

All workstations use the SAMBA server as standard gateway and
name server. The SAMBA machine uses the SQUID-proxy as standard
gateway, which is configured as transparent proxy and connects to
the internet via the DSL-router.

Now this is, what happens:
- workstations from 172.16.1.0 can ping everything and have
  internet access
- SAMBA can ping everything, but cannot connect to the internet
  by itself (I am running lynx on it)
- workstations from 172.16.11.0 can ping everything but the
  proxy and so cannot connect to the internet.
- "cannot connect to the internet" means: I can ping
  www.freebsd.org , its IP is correctly resolved, but cannot be
  reached.
- all subnets are set to netmask 255.255.255.0


Please mail all kind or ideas, so I have got something to check
on monday.

Thanks,

Uli.

	+---------------------------+
	|    Peter Ulrich Kruppa    |
        |         Wuppertal         |
        |          Germany          |
        +---------------------------+