destination host unreachable from client

[anthony wooldridge]

I have a small network winxp and others that used to work ok,
but now only the host can acess the internet
The client cannot ping external IP numbers.
but can ping internal IP numbers
pinging www.bbc.co.uk for example attempts a ping on 212.58.224.124 but
fails "destination host unreachable"
the same command from the host works ok.
so I guess DNS lookup is working ok from client.

this is the result of ipcofig /all on the host:

C:\Program Files\Support Tools>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : xp2000
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : Yes
WINS Proxy Enabled. . . . . . . . : Yes

Ethernet adapter Network Bridge (Network Bridge) 8:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : MAC Bridge Miniport
Physical Address. . . . . . . . . : B2-56-29-8D-60-BA
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.0.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . : 127.0.0.1

PPP adapter freeserve anytime:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : WAN (PPP/SLIP) Interfac
Physical Address. . . . . . . . . : 00-53-45-00-00-00
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 81.78.112.132
Subnet Mask . . . . . . . . . . . : 255.255.255.255
Default Gateway . . . . . . . . . : 81.78.112.132
DNS Servers . . . . . . . . . . . : 195.92.195.94
195.92.195.95

the client ipconfig is similar except:

IP routing and WINS proxy not enabled
IP address 192.168.0.172
DNS servers 192.168.0.1

 

[Steve Duff [MVP]]

The ping message means that your ICS host isn't routing
the traffic through to the Internet side.

The usual reason for this is that you've configured
a software firewall of some sort that is inadvertently
blocking the traffic.

I assume from the ipconfig that you are using a
dial-up modem. A NAT router would solve your
problem inexpensively, but sadly dial routers
are very difficult to find as nobody is doing them
at the low end. If you can find a Netgear dial router
on ebay or whatever, it would be a worthwhile
investment.

Steve Duff, MCSE
Ergodic Systems, Inc.

 

[anthony wooldridge]

The ping message means that your ICS host isn't routing
the traffic through to the Internet side.

The usual reason for this is that you've configured
a software firewall of some sort that is inadvertently
blocking the traffic.

I did install zonealarm, ( but the problem predated that installation),
and I did once have mcafee firewall running and win XP IPS firewall
however I have turned them all off on occasion to test if it enables the
routing but it does not.
I think it might be a service that has stopped running but which one?

I assume from the ipconfig that you are using a
dial-up modem. A NAT router would solve your
problem inexpensively, but sadly dial routers
are very difficult to find as nobody is doing them
at the low end. If you can find a Netgear dial router
on ebay or whatever, it would be a worthwhile
investment.

I could check out the NAT router option but the system was all working
for a long time, something has caused the host not to route properly
but how to check what's not working?

Anthony

 

[Steve Duff [MVP]]

I'd recommend that you de-install all of the firewall
software and test, as the problem may not be a service
that isn't running, but a service that still is.

The problem may be that the routing table in the client
isn't correct. Use a "route print" command from
a CMD prompt to verify that there is a default route
to the server 0.0.0.0/0 ==> 192.168.0.1), and you also
can use "tracert <some-public-ip>" from the client just to verify that
it is sending through the correct gateway (the server address
192.168.0.1).

Steve Duff, MCSE
Ergodic Systems, Inc.

 

[anthony wooldridge]

Bingo! thats it,
it was the route missing on the client.
I was so convinced the problem was in the host.
From cmd I did a
route add 0.0.0.0 mask 0.0.0.0 192.168.0.1 metric 1
(no idea what the metric is for but put it in anyway,
I just copied it from the route print of a client that was working
(I must have fixed the original problem in the host without noticing
I think it may have been setting up the host in zonealarm for ics/nat
gateway)
and it all works now thanks.

Anthony

 

[Steve Duff [MVP]]

The missing route means that you don't
have a default gateway set. What you did
will work, but when you reboot you'll have
to do it again. You can add a "-p" to make
the route persistent, but better is to fix
the default gateway. If you are using DHCP,
the DHCP server isn't handing out a default
gateway. If you have a static configuration, just
fill in the default gateway field with the IP
address of the router.

Steve Duff, MCSE
Ergodic Systems, Inc.

 

[anthony wooldridge]

OK got it now!
Fixed the default gateway in the client nic tcp/ip properties.
Thanks for that it's been driving me mad for weeks!
Anthony