Hi guys, I was hoping somebody may have come across this issue before and might have a fix. We have a customer with a 2.4Ghz wireless network in a resort, the AP's are all RB411AH units and seem to be working fine in general. The AP's are backhauled to the main building using some Omnitiks and SXT's, the backhaul is very reliable and stable, average signal is about -55, these are running in A/N mode and happy. The AP then connects into our hotspot gateway and everything works happily. All customer AP's are bridged back to the hotspot gateway via EOIP tunnels, once again that works fine. For management we have a VPN from each device which goes back to our data centre, as the backhaul network and all devices are fully routed these VPN's just travel across the network and out the Internet connection and work fine. The problem we have is that we have upgraded a couple of AP's and backhaul radios to v6.11, they were previously 5.4, as soon as we upgrade them we can't winbox to them anymore. We first noticed the issue a couple of days ago and didn't really think the upgrades were the cause, but I have spent a couple of hours tonight just going through configs, firewall rules, ACL's etc trying to find some reason why winbox won't work to these units, I have now got to the point where I reckon that it's something to do with the upgrades as the units which still haven't been upgraded connect up instantly without an issue. I thought I might be the winbox cache on my windows 7 PC so I deleted it, I can connect fine to other routers which I have upgraded to v6.10, but not with 6.11 or 6.12 which is what I am using on these radios. Has anybody come across this issue before and have any suggestions as I am all out of them now. The curly one with this problem is though that the issue only occurs when accessing the routers via VPN, direct access works fine, and I have reduced MTU's and tried everything but they should work with the same PPTP settings as the other routers on V5.4 as they are connected exactly the same way and are configured exactly the same way with exception to the ROS version. Any suggestions would be greatly appreciated ! although I am happy with CLI it's just easier to do some things in the GUI and you can see graphs and stuff J Thanks Paul