Ping is broken...

[GalaxyAdmin]

Hi all,

We have stores all over the country each with their own PC with 3G card, connecting via a Billion router with a VPN connection.

At a few of the stores I have had a few issues - what it comes down to is that when I try to ping a server on the network at headoffice(i.e. exchange) the ping resolves the correct IP - but then it replies from a different IP.

Below is what I get when running such a ping...does anyone have any ideas as to what the problem might be?


C:\Documents and Settings\administrator>ping ***ex

Pinging ***ex.********.com [192.168.0.10] with 32 bytes of data:

Reply from 192.168.0.19: bytes=32 time=148ms TTL=126
Reply from 192.168.0.19: bytes=32 time=123ms TTL=125
Reply from 192.168.0.19: bytes=32 time=124ms TTL=125
Reply from 192.168.0.19: bytes=32 time=125ms TTL=125

Ping statistics for 192.168.0.10:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 123ms, Maximum = 148ms, Average = 130ms

 

[adielh]

It gets directed from a proxy that's why its a different address

 

[adielh]

oh Ya dude never give you IP on a forum ,there are strange people out there

 

[[email protected]]

192 is an internal IP address so there is no RISK at all. I know my copany's internal IP address also starts with 192

 

[MadMailMan]

oh Ya dude never give you IP on a forum ,there are strange people out there

Not really a problem, guess you didn't notice that it's inside his VPN and it's a private address (192.168.x.x).

Is your exchange box behind another firewall. You can configure certain firewalls to reply to ping/tracert/etc for the entire network behind it. Try telnetting in on port 25 and see if you can connect. Have you worked out what the device is that is replying? Is it a router? If yes it may need a bounce, or check it's logs to see what it thinks it is doing.

 

[GalaxyAdmin]

hey adielh...

are you talking about an internet proxy?

why is it that i get replies from other servers on my network from their own IP's, but only this one replies from another IP?

 

[gregmcc]

What servers are on .10 and .19. If you traceroute to them to the both go via the same network?
You might have some ARP poisoning - if 2 IP's had the same MAC they could response with something similiar?

 

[Conradl]

OS?? Is your firewall service running? Vista/2008/Win7 does what you describe if you turn off the firewall....

 

[werner]

your firewall device needs to support 1:1 nat so you can assign a specific external ip to map to an internal ip for outbound traffic.

in your scenario above, the dns name resolves to the correct machine, which has icmp etc port forwarded by the looks of it correctly, but the reply is coming via the visible external ip, which in this case is also in the 192 range (external, as in from the box viewpoint, not from the whole internet ...so probably a firewall or gateway device)

if you have iptables installed, then have a look at SNAT for the .10 machine

 

[GalaxyAdmin]

.10 would be the local machine IP (in the store connected via 3G & VPN so it has a local address - each store has its own subnet) and .19 would be the ISA box - our headoffice firewall.

what confuses me further is that it used to work up to a while ago, and from then the exchange ping replies with the firewall IP.

the store machines are running winXP
the firewall is on Win Server 2003
and the exchange box is on Win Server 2008

 

[Conradl]

Have you checked that the firewall service is running on your exchange server? I have the exact same problem with 2008 machines....

 

[adielh]

Hi Galaxy ,

Tel me if I'm correct, you guys are running windows terminal server with dhcp mode , with Remote vpn to logg on to the sever from any branch,using terminal session?? You have a Radius mail and domain server, all incl in the terminal server,

 

[GalaxyAdmin]

Hi Conradl, the firewall is indeed on. but why do i only experience this problem from one of the stores? all other stores ping the exchange on its correct IP.

Hi adielh, no. each site has a Billion router which acts as a DCHP(and is setup with the VPN connection - which runs over a 3G connection). each store has a machine(connected to the router via UTP cable) with a SQL DB on which they capture their data and this SQL replicates every evening. if need be i terminal into the store machine to provide support. hope that answers your question...

 

[adielh]

wow i run the same setup, but its flawless using terminal server. Currently I run that setup with a VMware , so its hassle free

 

[adielh]

Well it could also be that those pc run vista , and have IPv4 and ipV6 addresses which your dhcp cannot assign, and give a default router address

 

[GalaxyAdmin]

hehe...nice.

all the store machines run Windows XP. the router serves as the DHCP on each subnet and it assigns itself as the Default Gateway on that specific subnet.

 

[GalaxyAdmin]

hey all...thank you for your input & ideas. i have managed to fix the problem with the assistance of a rather clever oke. it was a routing problem, after adding the routes the pings went through to the correct IP & I was able get the data where it needed to go.

once again...thank you