RTT 3000 on all nodes.
I have the same problem with Path of Exile RTT 3000 on all nodes…
Did you try to change “RTT Checking Method” option from UDP to ICMP or TCP? It seems there are network firewall on your environment and blocks UDP.
Really? Weird because some of RTT information looks good but other RTT information to other mudfish nodes are still failed because other’s RTT is still 3000 ms. Please confirm it for me. 
@Xenta please check it again. I’d found a problem of RTT checking for London region and had updated the information.