tag:blogger.com,1999:blog-3993498847203183398.post1245749659950940108..comments2024-03-29T11:00:39.953+00:00Comments on RevK<sup>®</sup>'s ramblings: Next step in AP testing hereRevKhttp://www.blogger.com/profile/12369263214193333422noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-3993498847203183398.post-35285905929712913092017-04-10T13:03:40.673+01:002017-04-10T13:03:40.673+01:00That thread progresses and a couple of people are ...That thread progresses and a couple of people are suggesting that "Wifi Assist" may be an issue for link-local addresses.<br /><br />Seems entirely plausible to me that "Wifi Assist" may be causing a race condition when roaming between APs with the same SSID.<br /><br />As is often common the "community" may know more than the manufacturer's support people :)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-81961303275209241002017-04-09T14:28:44.977+01:002017-04-09T14:28:44.977+01:00Is there nothing you can put on the iphone like wi...Is there nothing you can put on the iphone like wireshark - or do you have to "jailbreak" it?<br /><br />I suspect you're going to need to run a TCP dump on both ends (iphone & AP) on a daily basis until it fails. <br /><br />That's the only way to see what triggers it at the IP layer.<br /><br />However I suspect that what you're seeing is at the PHY layer and is a bug or a workaround in iOS for some engineering defect in the device's design. <br /><br />I speculate here, but given Apple has history for this on the RF side I'd think it likely if not probable the latter is the case.<br /><br />Best of luck - if you do work out what it is and it is in fact iOS then I'd charge Apple for your work. <br /><br />If iOS was even as "open-source" as Android then no, but its Apple's walled garden so they can pay the maintenance costs ;)<br /><br />Didn't Apple stuff used to "just work"? <br /><br />I refer to your TV stuff (not the first tale of woe I've heard on that) and various iOS upgrade nightmares I've had recounted to me over the last decade. <br /><br />Maybe it "just worked" when they didn't have many customers - or when they weren't so interested in monetising them. I digress :)<br /><br />Best of luck, if anyone can nail the cause here it might just be you....Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-20804726071873593552017-04-09T09:52:47.989+01:002017-04-09T09:52:47.989+01:00Don't know if you saw this (dated 8/4/17) :
h...Don't know if you saw this (dated 8/4/17) :<br /><br />https://community.ubnt.com/t5/UniFi-Wireless/Problem-with-iPhones-roaming-between-access-points-including-in/td-p/1892537<br /><br />tl;dr of post seems to be the iphone not renewing the IP lease even when specifically told to do so.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-85971055410490271222017-04-07T19:38:25.224+01:002017-04-07T19:38:25.224+01:00This is sounding more and more like the problem a ...This is sounding more and more like the problem a client had (makoto's previous place). There was a subnet off the FB2700 with three UniFi APs (WPA2) and various wired machines for 'guest' and non-domain computers. Periodically clients couldn't get DHCP assignments and it looked as if the FB was ignoring requests. I think I observed it on other devices but it was primarily Apple clients that were affected. In an attempt to partition the problem I split the wired and wireless onto separate subnets with separate DHCP ranges and the problem simply went away.JJhttps://www.blogger.com/profile/15638774441452806449noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-19996608199666663182017-04-06T09:59:07.440+01:002017-04-06T09:59:07.440+01:00For what its worth, we've seen roaming problem...For what its worth, we've seen roaming problems with iOS devices on Ruckus wifi kit (no Firebricks), but this seemed to be specifically related to using 802.1x and didn't occur with plain old WPA, so possibly not the same problem. I've also seen an article on the Cisco knowledgebase saying there are known problems with iOS devices roaming on Cisco access points.<br /><br />Although the factors that set this problem off in each case seem to be different (e.g. Ubiquity + Firebrick in one case, Ruckus + 802.1x in another, etc.) it may all be the same iOS bug that is somehow being triggered by something that's common to all of these setups, even if that's something completely obtuse like "the bytes at offset in one of the wifi packets happen to spell 0xc0ffee" :)Steve Hillhttps://www.blogger.com/profile/09798286430189689578noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-4093623430492866862017-04-06T07:00:27.943+01:002017-04-06T07:00:27.943+01:00I am glad you found a work around. That is another...I am glad you found a work around. That is another piece of the puzzle, certainly. Here I cannot now make it go wrong so cannot repeat my non-DHCP testing, sadly. This is also useful as another non FireBrick case, suggesting it is something in network set up (we know IPv6 is a factor) such as DHCP settings which may be more common on some gateways.RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-37849035229545705412017-04-05T21:23:49.798+01:002017-04-05T21:23:49.798+01:00I hesitate to make a suggestion based on very circ...I hesitate to make a suggestion based on very circumstantial evidence after so much intensive investigation by so many but, for what it's worth...<br />I had apparently the same problem last year where the only common factors were i-things and IPv6, no Ubiquiti, no Firebrick. Well, the problem I had was more consequential but, once my ears had recovered and, on the occassions that I caught the i-thing mid-flight, I was able to confirm that it had just a 169... address. The real sufferer had generally just roamed from the kitchen with a cup of tea looking forward to continuing with her article on Mumsnet (or somesuch) from an armchair. <br />The three APs involved are just old home routers (but all 5GHz). DHCP (IPv4 and IPv6) was by ISC DHCP servers on an OpenSUSE machine. I rebuilt the OpenSUSE machine at the New Year and 'temporarily' enabled DHCP on the Draytek router and SLAAC for IPv6. Temporarily hasn't ended yet and the i-things have behaved perfectly for 3 months. What can this mean?<br />Could it be that something about a DHCP lease with certain characteristics sets an i-thing up for failure at its next WiFi roaming event? A race between IPv4 and IPv6 assignment? A clever option offered by the more sophisticated DHCP server that is 'mis-interpreted' by the i-thing in the context of a proprietray roaming extension? I don't know but if I had the tools and skills I'd try to correlate failed roams with whatever happened at the previous address assignment. All with apologies for lack of knowledge and too much guess-work.Don't argue with the cooknoreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-5478363251313839102017-04-05T17:41:59.070+01:002017-04-05T17:41:59.070+01:00You're probably going to want to simultaneousl...You're probably going to want to simultaneously log both the wired backbone and the wireless traffic to form a full view. If there's some kind of inter-access point management traffic on the backbone you could miss it if you're only monitoring 802.11. At one point I think Ubiquiti supported 802.11F/IAPP but I assume they replaced that with something else when it was withdrawn. Technical Vaulthttps://www.blogger.com/profile/06706968838212709673noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-6504935663399244972017-04-05T17:17:18.285+01:002017-04-05T17:17:18.285+01:00Seems unlikely a dumb switch would fail in a way t...Seems unlikely a dumb switch would fail in a way that would break roaming on their APs, but nothing else and it *not* be UBNT's fault. I'll try and pull an extra cable so the APs can both be directly in the router's switch... Anonymoushttps://www.blogger.com/profile/14634685104014626934noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-72045235345520880492017-04-05T13:56:57.838+01:002017-04-05T13:56:57.838+01:00We had some net gear here. I thought I had elimina...We had some net gear here. I thought I had eliminated switches as the cause. I wonder.RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-83121430580664646022017-04-05T11:34:07.543+01:002017-04-05T11:34:07.543+01:001 AP is connected directly to a gigabit port on th...1 AP is connected directly to a gigabit port on the Mikrotik router (RB2011). The other is connected to the same switch group on the router via two bog-standard netgear unmamaged switches (router - GS108 - GS208 - AP). Both APs are UAP AC Lite. Anonymoushttps://www.blogger.com/profile/14634685104014626934noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-74193406922958838262017-04-05T10:43:03.646+01:002017-04-05T10:43:03.646+01:00Thank you for confirming, that is exactly what we ...Thank you for confirming, that is exactly what we were seeing. And I am glad it is not using a FireBrick as Brandon seems to latch on to any explanation and repeat it ad nausiem. Now we know for sure it is not FireBrick specific. Can you confirm what switches you use?RevKhttps://www.blogger.com/profile/12369263214193333422noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-87576851900372110742017-04-05T10:02:46.266+01:002017-04-05T10:02:46.266+01:00I had another bad case of this last night. I get t...I had another bad case of this last night. I get the distinct feeling this happens when I am getting roughly equal signals from each AP, perhaps something in the roaming logic is broken on UBNT's side. Sometimes it resolves quickly so I just notice a long pause in IPv4 connectivity. However, sometimes the iOS device reverts to a 169.254 address (but maintains the IPv6) and I have to disconnect/reconnect to get my IPv4 back exactly as you described. <br /><br />This is using a Mikrotik, not Firebrick router - no fancy/complex setups just DHCP IPv4 and SLAAC'd IPv6 and router in the same building :). <br /><br />Anonymoushttps://www.blogger.com/profile/14634685104014626934noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-66001519454956693152017-04-05T09:10:45.348+01:002017-04-05T09:10:45.348+01:00"Trouble keeping it there" might be Netw..."Trouble keeping it there" might be NetworkManager's fault - make sure its shut down and stays shut down.Steve Hillhttps://www.blogger.com/profile/09798286430189689578noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-31778807641694472752017-04-04T23:37:23.597+01:002017-04-04T23:37:23.597+01:00Wireshark on linux with a suitable wifi dongle (I ...Wireshark on linux with a suitable wifi dongle (I was using one of OmniPeak's adaptors) does a good job of capturing all on-air traffic when in monitor mode.<br />If the WPA key used for the test is provided, then traffic can be decrypted.<br />I do remember that it took some manual convincing at the command-line outside of wireshark to get the adaptor into the right mode and trouble keeping it there.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-24878662533688140412017-04-04T23:09:04.604+01:002017-04-04T23:09:04.604+01:00Btw there are bugs in iOS which mean that when it ...Btw there are bugs in iOS which mean that when it gets into a certain _state_ you can't save static IPv4 settings in the "settings > wifi" app. Once it gets in this state it just goes back to the dhcp pane when you go out and back into settings, and keeps doing this again and again. The fix is to do a "forget network" which seems to delete the problematic state information. Other users have complained about this in Apple forums. I have submitted detailed bug reports to Apple, via two different channels in the vain hope they might fix it. Just don't get caught out, as it is maddening and frustrating, and spread the word.Cecil Wardhttps://www.blogger.com/profile/16477035597238561739noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-47446235443971802602017-04-04T13:00:00.401+01:002017-04-04T13:00:00.401+01:00I don't know whether you have one to hand (I k...I don't know whether you have one to hand (I know at least one of your staff uses them) but MikroTik wireless access points have some pretty comprehensive WiFi sniffing capabilities.Johnhttps://www.blogger.com/profile/17555396036856701009noreply@blogger.comtag:blogger.com,1999:blog-3993498847203183398.post-42250119787097657592017-04-04T10:59:01.728+01:002017-04-04T10:59:01.728+01:00What about a separate machine with a wifi card log...What about a separate machine with a wifi card logging what is actually being sent over the air at the 802.11 protocol level? You should be able to see the client sending authentication requests, DHCP, etc (or not) and whether anything is actually replying to that traffic.Steve Hillhttps://www.blogger.com/profile/09798286430189689578noreply@blogger.com