We have an office in the UK (main office) and an office in the US. These are connected over a dedicated VPN link. Both sites have managed Cisco 1700 routers. The UK office contains all the servers and domain controllers. One day when i came into the office (UK) the US site could not log onto the domain. Also from the UK we could not map to any of the US Folders. When i pinged the US from the UK everything seemed ok (4 replies) however when i increased the byte size to 3000 bytes it started to time out.
After numerous phone calls to our ISP who manage our routers and VPN they could not work out why this was happening. I ran every test you could imagine on our domain controllers and LAN but to no avail. Left for the weekend, came back Monday morning ready to do battle and the Link was back to normal. I phoned our ISP to see what they had done over the weekend but they claimed they had done nothing. When i pinged the US everything was ok, pinging up to 10000 bytes and over no problem.
Is their any reason why i could not ping the US with a byte size over 3000?
Also a point to note, during the time when the link was not working the US could still dial direct into our RAS (bypassing the router), log on, receive e-mails etc.
This has been really annoying me as their has been no explanation why this happened either from our ISP or from myself and i do not want this to happen again.
Any ideas would most appreciated.