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I have a VPN set up between several offices. All but one work fine. With one office, I can ping the printer 192.168.45.30 but not a server 192.168.45.242. Well, I say I can't but when the server was first powered up, I could ping it for about 30 seconds and then it disappeared. I can still ping it from the remote router (local to the server) but not from my desktop across the VPN.

This problem has been going on for some time so I replaced the router at the remote office with a similar (not identical) router and had the same problem.

I had Draytek support look at the routers and they seem fine.

I set up the original router at my home and created a VPN connection to there, set up a duplicate server and everything worked as expected. I sent the duplicate server to the remote office... I can ping it a little as it starts up then it dissappears.

Head Office 192.168.42.0 (Firewall / VPN concentrator Draytek Vigor 2955 through a Cisco 1841 router
My PC 192.168.42.249

Remote office 192.168.45.0 (Draytek Vigor 2830 ADSL router
Remote printer 192.168.45.30 (can ping)
Remote server 192.168.45.242 (can't ping)

Home office (using old Draytek Vigor 2820 router from remote office) 192.168.5.0
Duplicate server 192.168.5.237 (could ping etc but now at remote office)

As far as I can see the routers are working correctly and so is the server so where is my connection being blocked?
Can another device on the network block the connection to the server? At present the server is plugged directly into the router.

Unfortunately it is difficult for me to get to the remote office and I obviously have restricted connectivity, but any ideas of things I could check or try would be much appreciated.


Ah ha! I just asked somebody at the remote office to unplug everything from the router except the server and I can get a stable connection to it. So it must be another device on the network. Any suggestions where to look?


Edit after fixing the problem by changing IP address of server to 192.168.45.29
I can't ping 192.168.45.242 from my workstation, but I can still do so from the remote router, so there is obviously something there, but it must be set to only respond to local pings.

10

Since you are temporarily able to ping the server, VPN and ACLs should be fine.

I recommend to verify:

  • A local firewall on the server could block the ICMP requests. The fact that it responds at startup, but stops later, leads to this assumption.

  • There may be an IP conflict, i.e. another device in the network with the same IP. That cause is possible since it works if you unplug all other devices.

  • Thanks for the reply, The fire wall on the server is off, the IP conflict is possible. I was thinking of changing the IP address of the server to 45.29 or 45.31 similar to th eprinter to see if that makes a difference. – Jaydee Jun 7 '13 at 9:35
  • @Jaydee Ping the new addresses (and check the documentation if they would already exist) - so you don't accidentally cause an IP conflict with the other addresses. – Stefan Jun 7 '13 at 9:51
  • OK I've pinged 45.29 it and it seems clear. There shouldn't be anything there as far as I can tell. – Jaydee Jun 7 '13 at 9:58
  • It looks like that has sorted it! So simple (with many years of experience). Many thanks for your help. – Jaydee Jun 7 '13 at 10:09

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