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Author Topic: Ubiquiti WAPs and iOS (contd)  (Read 2043 times)

Weaver

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Ubiquiti WAPs and iOS (contd)
« on: March 31, 2017, 12:09:46 PM »

RevK is continuing his battle to debug problems with Apple iOS boxes on Ubiquiti WLANs. It seems to depend on a heap of things all being true:

   http://www.revk.uk/2017/03/where-are-we-with-unifi-and-iphone.html#comment-form
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burakkucat

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #1 on: March 31, 2017, 05:38:29 PM »

If I have read that correctly he is now pondering the possibility that it is his code in his Firebrick devices that may be at the root of the problem.  ::)

Time will tell.  :-\
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #2 on: March 31, 2017, 05:51:06 PM »

I thought I saw a mention of a non-Firebrick case in the comments. I can't see how a router could make an iOS box fail like that, well I ought to know more about it, it could be that the iOS device tries to reacquire an IPv4 address when it does a BSS handover.

I'm more inclined to think that something as nasty as that would be a tread on the wrong floorboard kind of bug, that you need say a Firebrick plus x plus y etc to be the correct stimulus to make something else fail. Instinct would point the finger at Apple. But also because, looking at it from another angle, an argument could be made that Apple have screwed up regardless of the details, in that there is no earthly reason for them to end up with an IPv4 link-local address (169.254.x.x).

I would definitely think that a Firebrick has to be blameless because it knows nothing about wireless LANs and any plain networking protocol bug - perhaps relating to DHCP - would have been spotted in traffic captures or logs by now.

Just a load of guesswork from me based on far too many months of my life wasted, but zero knowledge of this situation.
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currytop

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #3 on: April 01, 2017, 10:36:00 AM »

That makes a more interesting read in that he gives more information. I don't have that issue but then I did turn off IPv6 support a couple of months ago because I didn't trust my IPv6 firewall. Only the IP phones seemed to prefer IPv6. But again I don't remember having an issue before that. Also all the networking kit is now Ubiquiti - edgerouter, non-Unifi POE edgeswitch, and Unifi APs. Oh, apart from a dumb gigabit switch.

As a matter of interest I don't use DHCP on the edgerouter but dnsmasq instead which is also built-in. It finally gives me seamless name resolution on dynamically allocated addresses for the internal network without having to configure static addresses with a DNS server, or having to couple DHCP & DNS servers. Dnsmasq also provides IPv6 RA/SLAAC when desired. In the latter case however you do need to edit the configuration tree but can still do so from the web GUI.

In the RevK's case I wonder what the result would be turning off Firebrick DHCP & RA and temporarily placing another device to perform that function. I don't envy him the task of analysing all the traffic captures.
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #4 on: April 01, 2017, 07:55:20 PM »

Currytop, just for clarification- as far as I am aware, Firebricks can only do DHCPv4 not DHCPv6 so without a separate server RevK will presumably not be using DHCPv6.

I would like to sort out internal DNS for IPv6 assignments but I don't see how I can do it because, in the context of IPv6, all the hosts I happen to have do their own random thing regarding IPv6 address allocation and are not managed by a DHCPv6 server. Would your approach work using a server that can be added on to my network separately? I do IPv4 address assignment by letting a Firebrick acting as DHCPv4 server manage all hosts. It happens to hand out assignments that are fixed according to a MAC-to-IPv4 mapping table that is in the Firebrick's config. So they appear static / fixed.
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currytop

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #5 on: April 01, 2017, 08:31:41 PM »

It seems DHCPv6 is rarely used these days, folk preferring to use RA/SLAAC. So hosts select their own IPv6 addresses within the allowed range. For something different an individual host needs the ability to select different methods to obtain addresses such as DHCPv6. In that case I can't see any reason a separately configured DHCPv6 server couldn't be used. You could stick with fixed address allocations via DHCPv6 as well although it seems a lot of work if many devices are involved.

I did think however that the Firebrick supported dnsmasq. If so you could use that to provide what you want although may need to manually configure it. I'm not really familiar with how the Firebrick is configured though. Dnsmasq can provide name resolution for IPv6 clients that use DHCPv4 but RA/SLAAC for IPv6. Dnsmasq mamnual is available here: http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html
« Last Edit: April 01, 2017, 08:43:28 PM by currytop »
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aesmith

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #6 on: April 02, 2017, 12:37:44 PM »

It seems DHCPv6 is rarely used these days, folk preferring to use RA/SLAAC.
Moving off topic a little, in those scenarios what do you use to push out all the other stuff normally served by DHCP, things like DNS servers, domain suffix, special settings via DHCP options?   Or do you just mean DHCP not used for host address and default gateway assignment.
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currytop

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #7 on: April 02, 2017, 05:38:34 PM »

Not sure if you're talking IPv6, but in that case DHCPv6 doesn't support full network configuration ala DHCPv4. Most things can be configured using router advertisements.  If more control is wanted then a flag can be set to indicate to clients to issue DHCPv6 requests. Whether they honour it is up to them.
What I meant in reference to dnsmasq was that the DHCPD program itself wasn't used, but dnsmasq can still answer DHCP & DHCPv6 queries in addition to RAs if so configured.
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #8 on: April 04, 2017, 11:01:36 PM »

More developments in the Ubiquiti - Apple saga, possibility of some progress?
    http://www.revk.uk/2017/04/working-with-ubiquiti.html
    http://www.revk.uk/2017/04/next-step-in-ap-testing-here.html
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aesmith

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #9 on: April 06, 2017, 04:01:22 PM »

Interesting.  I've not gone through it all, but on the face of it if the router seems to be a suspect, wouldn't a capture taken at the router's LAN interface give some idea of what's going on?   
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #10 on: April 06, 2017, 04:20:47 PM »

I don't see it that way, because didn't it say there is one case of failure where no Firebrick was involved. I am assuming that using the Firebrick might just be a good way of setting up the critical test conditions for the whole complex system to fail.
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aesmith

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #11 on: April 06, 2017, 06:05:39 PM »

Maybe, or it may be that the other router has the same issue as the Firebrick.  It seems that the Rev tested with a Ubiquiti router and the problem went away, while Ubiquiti tested with Firebick (problem) and other routers (no problem).  If I was doing that I'd be tracing at the router for a good and bad scenario and looking for differences.
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #12 on: April 06, 2017, 09:56:48 PM »

I suspect he's stuck because of lack of tools to do an RF traffic capture.
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aesmith

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #13 on: April 07, 2017, 03:44:54 PM »

My point was that if the type of router has any effect at all, that should be visible in traffic on the LAN at the router interface.
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Weaver

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Re: Ubiquiti WAPs and iOS (contd)
« Reply #14 on: April 07, 2017, 08:47:15 PM »

@aesmith - yes, you would think so wouldn't you? And that's why I find it hard to believe the router is morally responsible, as it would have been spotted in a traffic capture, you would think.
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