On 8/18/2016 2:41 PM, Scott Lambert wrote: > On Thu, Aug 18, 2016 at 08:55:29AM -0500, Sam Morris wrote: >> There is nothing in the event section of the AC2 server, nor is there >> any indication of the MTU size getting changed in the radio's logs. >> (There is an entry in the event log from when I changed it from 1492 -> >> 1500 bytes, but that's the only thing related to this.) (I checked >> Saturday and Sunday's logs - nothing to indicate the MTU size was >> changed.) I'm continuing to investigate - if anyone has another thought >> I'd welcome it :) > > Maybe the AP has been set that way for a long time. > > Did you recently change any firewall rules to block ICMP? > > If ICMP is working, PathMTU discovery can work and connections can deal > with arbitrary MTU limits along the path. The TCP/IP stacks just lower > the MSS until they no longer receive ICMP packet too big responses.
Hi Scott, Nope, I'm positive nothing changed on the firewall. (No one other than me has the credentials to login to either the AP or the firewall.) I did consider it, but really don't think the AP MTU size could've been set like that all along as it was completely preventing customers (especially those with a Mac) from working; as soon as I changed it to 1500 they immediately started working again. My thinking is if it had been set that way all along they wouldn't have ever worked (they've been working for months). At this point, after going through all the AP logs and AC2 logs, I have to think that there was something in that wonky switch port that must've somehow caused the setting to change. I can't prove that, but can rule out anything else (assuming the logs can be trusted). I did see entries from other APs where I was experimenting with increasing the MTU size - each time I made a change there was a corresponding log entry in both the AP log as well as the AC2 log. The only recent entry is from when I increased it from 1492 to 1500. There were 15,000+ errors on that port on the Netonix, and while I find it difficult to believe the switch caused that setting to change like it did, I can find nothing else remotely close to offering reasonable suspicion, short of a hacker getting into the Rocket and changing it - but were I to hack an AP, changing the MTU size wouldn't be high on my list of things to do once I gained access.... :) Sam _______________________________________________ Ubnt_users mailing list Ubnt_users@wispa.org http://lists.wispa.org/mailman/listinfo/ubnt_users
