PING timeouts. ARP entries ok.

[mark gramlich]

Here's the background.

Small network of five systems. One W2K server, two W2k Pro and two
WINXP home. No one ever started DHCP on the server. Thus all the
systems are using 196.254.x.x addresses. Each had a 255.255.0.0 mask
with no default gateway. Only dial-up access to the Internet from
individual machines. No one kept up with Windows Update.

They decide to use the local cable company for broadband access. A
Cisco PIX 501 firewall is installed with a 196.254.1.1 address. Used
IPCONFIG to pick up the existing IP address on each system. Changed
the TCP/IP config on both WINXP systems to use the new gateway. No
problems. Changed the TCP/IP config on one W2K system to use the new
gateway. IPCONFIG is correct (right IP address, mask and gateway). No
problem. Connected to Windows Update site. There were 20+ critical
updates behind. Pulled down and installed the oldest 7 updates
(Q811630, Q810833, Q810649, Q329170, Q323255, Q326886 and Q326830).
Rebooted. Now unable to PING anywhere. Not to the Internet. Not to any
local machines. Since the only changes were the updates, I backed out
the one in Add/Remove programs. This removed Q810833, Q329170, Q326886
and Q326830 and rebooted. Still cannot PING anywhere. The TCP/IP
settings look ok. Changed the IP address of this system. Still cannot
PING. Determined that SP4 was not installed. Installed SP4 and
rebooted. Can PING again. Everything appears fine. Went back to
installing critical updates. Pulled down and installed KB823182,
KB823559 and KB824105. Rebooted. Now PINGs fail again!!!

Did some further checking and had these observations.

1) PING's timeout to both local and Internet names and local or
Internet IP addresses.
2) There are correct ARP entries in the ARP cache for local IP
addresses.
3) The W2K system still has the ability to map file/folders on the
W2K server.
4) The W2K system can PING itself. Both by IP address and name.
5) NETSTAT -R does show a default route (0.0.0.0) to the Cisco PIX
(196.254.1.1).

At present, my next step would probably be to turn on DHCP on the W2K
server and use 192.168.0.20 thru 192.168.0.39. Change the IP address
on the firewall and the server. I'm entirely comfortable with this as
I don't understand the root cause of the problem.

I'm open to any thoughts, ideas, comments or suggestions.

 

[Phillip Windell]

At present, my next step would probably be to turn on DHCP on the W2K
server and use 192.168.0.20 thru 192.168.0.39. Change the IP address
on the firewall and the server.

That is what I would do. But I would use a higher number in the third octet.
If you ever at any time want to setup VPN with another private network, you
both must be using different private address sets. Both 0 and 1 in the third
octect are way over used and some "home user" broadband routers are
hardcoded to use one of those two and it can not always be changed,...so
stay away from 0 or 1 in the third octet.