Intermitent WAN issues
Posted on 2012-08-29
We have a managed MPLS VPN between our office in the UK and our office in China. All was working fine until the weekend where something changed and it became very unreliable
Ping and traceroute between sites is working fine with no apparent routing issues. There is no or very little packet loss. The problem is with any other traffic. Windows Networking, RDP, VNC and Http traffic all fails to connect 99% of the time. Every so often it will work but not for long. Each service has been tested locally and they work fine. Generally connecting from UK to China is a bit more reliable than China to UK for example in the UK I can view the windows shares on the China servers but not the other way around. RDP wont connect at all in either connection. Http will connect from China to UK around 40% of the time and to one server only
It's like there is a firewall blocking traffic but there isnt. The routing path is pretty much source --> default gateway --> ISP router --> WAN --> ISP Router --> destination
We're not aware of any network changes but then I'm note sure of what network changes would cause this especially when Ping/routing is fine.
Does anyone have any suggestions on what tests I can try to isolate the problem? The ISP is also investigating but they dont have an answer yet