[SlugLUG] Campus wireless problem: gateway in wrong network

[Peter Belew]

I've had the following problem a number of times around the campus.
At times, DHCP from the Cisco wireless routers assigns the gateway
address and the broadcast address in a different subnet from the
IP address assigned to the wireless NIC. On Linux, the IP software
can't handle this, while for some strange reason Windows XP's software
doesn't mind, and connects successfully.

For example, a few days ago I couldn't connect from the Stevenson
coffeehouse using Linux, while I could connect from XP, from the
same dual-boot laptop.

Running ifconfig from Linux showed the broadcast address and
the IP being assigned in different networks (I didn't see if it assigned
a gateway; it may have refused due to the broadcast address being
bad)

Here's the output of ipconfig /all on the XP system:

Ethernet adapter Wireless Network Connection 2:

        Connection-specific DNS Suffix  . : ucsc.edu
        Description . . . . . . . . . . . : 802.11g Wireless CardBus PC Card
        Physical Address. . . . . . . . . : 00-E0-98-CE-EA-F3
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 169.233.69.201
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 169.233.68.254
        DHCP Server . . . . . . . . . . . : 128.114.142.18
        DNS Servers . . . . . . . . . . . : 128.114.142.6
                                            128.114.129.33

Note that the IP and the gateway are in the 169.233.69/24 and
169.233.68/24 subnets, respectively. But I was able to log on
to cruznet from XP!

I was seeing this last Spring a lot in parts of McHenry.

Another problem I've seen, which is not system-specific, is that at
times you can't get through to an authentication server to log on
the the Internet gateway. This was happening a lot at the very
end of the summer, and did happen to me a couple of times this
fall quarter.

Peter Belew