Re: [Ubnt_users] MTU Size Changes Itself on Rocket M2

2016-08-19 Thread Scott Lambert 
What's your PPPoE server?  Yesterday afternoon I got a call from a tech at a 
customer location.  Yahoo main page loaded.  The yahoo mail login page did not. 
 The customer's linksys router had lost the internet port a few years ago, so 
every device was using the ubnt radio in router mode with pppoe, 1492 MTU.  

I lowered the MTU on the tech's laptop and everything worked.  A bit later I 
noticed that the dynamic PPP MTU fixup rules on the MikroTik PPPoE server were 
at the bottom of the list and not being reached.  Moving those rules to 
position 0 solved the customer's issues.

I suspect most consumer routers are better at dealing with PathMTU discovery  
blackholes than Windows TCP/IP stack.  That *may* be why we only had one 
customer complaint.  I'm not sure why AirOS didn't handle it, if that's the 
case.

I'm not sure how the rules ended up out of order after months of correct 
operation.  I suspect it happened when I updated the mangle packet marking 
rules via a script.  But it could be a RouterOS 6.26 bug.  I've not dived into 
deeply enough to prove any theory.  I probably won't bother if it doesn't 
happen again.   I have scheduled it to upgrade to 6.34.6 tonight. 


On August 19, 2016 6:38:46 AM CDT, Sam Morris  wrote:
>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
>
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Re: [Ubnt_users] MTU Size Changes Itself on Rocket M2

2016-08-18 Thread Sam Morris 
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 :)

Sam

On 8/18/2016 8:19 AM, Alasdair MacLeod wrote:
> Are you using AC2?  Check the events logs for changes for changes (a cog
> icon should show on the graphs if any changes occurred and a new config
> was backed up).
>
> On 18 August 2016 at 14:04, Sam Morris  > wrote:
>
> Yes. AC2 latest beta.
>
> On 8/18/2016 7:34 AM, Adair Winter wrote:
>  > are you running aircontrol?
>  >
>  > On Thu, Aug 18, 2016 at 6:45 AM, Sam Morris  
>  > >> wrote:
>  >
>  > Have any of you ever known the MTU setting in the Network Tab
> on a
>  > Rocket M2 (AP) to change itself? I started getting calls
> Sunday morning
>  > (primarily from Mac users) saying some of their websites
> wouldn't load.
>  > To make too long of a story short, I found that the MTU size
> was set to
>  > 1492 on the AP. (We do use PPPoE, and the MTU on the CPEs is
> set to
>  > 1492.) It should have been 1500. Changing it back to 1500
> fixed all the
>  > issues.
>  >
>  > My question is this: Other than me, no one has the password
> to get into
>  > the AP. I hadn't been into it in many days (or weeks). Yet
> somehow the
>  > MTU size changed and it obviously happened sometime between
> Saturday
>  > (when things for my users were fine) and Sunday morning (when
> things
>  > became hinky). There were some storms in the area, however I
> don't
>  > believe there was a lightning strike (as if that would only
> change the
>  > MTU setting and not affect anything else on the radio, or the
> other 11
>  > radios on the same tower). There *was* a bad port on the
> Netonix switch
>  > it was plugged into, however as with a lightning strike, I
> wouldn't
>  > think even a shorted port on the switch would change only
> that one
>  > setting - I could see it defaulting the entire radio, but not one
>  > setting like that.
>  >
>  > Anyone ever seen anything like that?
>  >
>  > Thanks
>  > Sam
>  > ___
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>  > Ubnt_users@wispa.org 
> >
>  > http://lists.wispa.org/mailman/listinfo/ubnt_users
> 
>  >  >
>  >
>  >
>  >
>  >
>  > --
>  >
>  > Adair Winter
>  > VP, Network Operations / Co-Owner
>  > Amarillo Wireless | 806.316.5071 
>  > C: 806.231.7180 
>  > http://www.amarillowireless.net 
> >
>  > >
>  >
>  >
>  >
>  >
>  > ___
>  > Ubnt_users mailing list
>  > Ubnt_users@wispa.org 
>  > http://lists.wispa.org/mailman/listinfo/ubnt_users
> 
>  >
>
> ___
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> 
>
>
>
>
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Re: [Ubnt_users] MTU Size Changes Itself on Rocket M2

2016-08-18 Thread Alasdair MacLeod 
Are you using AC2?  Check the events logs for changes for changes (a cog
icon should show on the graphs if any changes occurred and a new config was
backed up).

On 18 August 2016 at 14:04, Sam Morris  wrote:

> Yes. AC2 latest beta.
>
> On 8/18/2016 7:34 AM, Adair Winter wrote:
> > are you running aircontrol?
> >
> > On Thu, Aug 18, 2016 at 6:45 AM, Sam Morris  > > wrote:
> >
> > Have any of you ever known the MTU setting in the Network Tab on a
> > Rocket M2 (AP) to change itself? I started getting calls Sunday
> morning
> > (primarily from Mac users) saying some of their websites wouldn't
> load.
> > To make too long of a story short, I found that the MTU size was set
> to
> > 1492 on the AP. (We do use PPPoE, and the MTU on the CPEs is set to
> > 1492.) It should have been 1500. Changing it back to 1500 fixed all
> the
> > issues.
> >
> > My question is this: Other than me, no one has the password to get
> into
> > the AP. I hadn't been into it in many days (or weeks). Yet somehow
> the
> > MTU size changed and it obviously happened sometime between Saturday
> > (when things for my users were fine) and Sunday morning (when things
> > became hinky). There were some storms in the area, however I don't
> > believe there was a lightning strike (as if that would only change
> the
> > MTU setting and not affect anything else on the radio, or the other
> 11
> > radios on the same tower). There *was* a bad port on the Netonix
> switch
> > it was plugged into, however as with a lightning strike, I wouldn't
> > think even a shorted port on the switch would change only that one
> > setting - I could see it defaulting the entire radio, but not one
> > setting like that.
> >
> > Anyone ever seen anything like that?
> >
> > Thanks
> > Sam
> > ___
> > Ubnt_users mailing list
> > Ubnt_users@wispa.org 
> > http://lists.wispa.org/mailman/listinfo/ubnt_users
> > 
> >
> >
> >
> >
> > --
> >
> > Adair Winter
> > VP, Network Operations / Co-Owner
> > Amarillo Wireless | 806.316.5071
> > C: 806.231.7180
> > http://www.amarillowireless.net 
> > 
> >
> >
> >
> >
> > ___
> > Ubnt_users mailing list
> > Ubnt_users@wispa.org
> > http://lists.wispa.org/mailman/listinfo/ubnt_users
> >
>
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>
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Re: [Ubnt_users] MTU Size Changes Itself on Rocket M2

2016-08-18 Thread Sam Morris 
Yes. AC2 latest beta.

On 8/18/2016 7:34 AM, Adair Winter wrote:
> are you running aircontrol?
>
> On Thu, Aug 18, 2016 at 6:45 AM, Sam Morris  > wrote:
>
> Have any of you ever known the MTU setting in the Network Tab on a
> Rocket M2 (AP) to change itself? I started getting calls Sunday morning
> (primarily from Mac users) saying some of their websites wouldn't load.
> To make too long of a story short, I found that the MTU size was set to
> 1492 on the AP. (We do use PPPoE, and the MTU on the CPEs is set to
> 1492.) It should have been 1500. Changing it back to 1500 fixed all the
> issues.
>
> My question is this: Other than me, no one has the password to get into
> the AP. I hadn't been into it in many days (or weeks). Yet somehow the
> MTU size changed and it obviously happened sometime between Saturday
> (when things for my users were fine) and Sunday morning (when things
> became hinky). There were some storms in the area, however I don't
> believe there was a lightning strike (as if that would only change the
> MTU setting and not affect anything else on the radio, or the other 11
> radios on the same tower). There *was* a bad port on the Netonix switch
> it was plugged into, however as with a lightning strike, I wouldn't
> think even a shorted port on the switch would change only that one
> setting - I could see it defaulting the entire radio, but not one
> setting like that.
>
> Anyone ever seen anything like that?
>
> Thanks
> Sam
> ___
> Ubnt_users mailing list
> Ubnt_users@wispa.org 
> http://lists.wispa.org/mailman/listinfo/ubnt_users
> 
>
>
>
>
> --
>
> Adair Winter
> VP, Network Operations / Co-Owner
> Amarillo Wireless | 806.316.5071
> C: 806.231.7180
> http://www.amarillowireless.net 
> 
>
>
>
>
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Re: [Ubnt_users] MTU Size Changes Itself on Rocket M2

2016-08-18 Thread Adair Winter 
are you running aircontrol?

On Thu, Aug 18, 2016 at 6:45 AM, Sam Morris  wrote:

> Have any of you ever known the MTU setting in the Network Tab on a
> Rocket M2 (AP) to change itself? I started getting calls Sunday morning
> (primarily from Mac users) saying some of their websites wouldn't load.
> To make too long of a story short, I found that the MTU size was set to
> 1492 on the AP. (We do use PPPoE, and the MTU on the CPEs is set to
> 1492.) It should have been 1500. Changing it back to 1500 fixed all the
> issues.
>
> My question is this: Other than me, no one has the password to get into
> the AP. I hadn't been into it in many days (or weeks). Yet somehow the
> MTU size changed and it obviously happened sometime between Saturday
> (when things for my users were fine) and Sunday morning (when things
> became hinky). There were some storms in the area, however I don't
> believe there was a lightning strike (as if that would only change the
> MTU setting and not affect anything else on the radio, or the other 11
> radios on the same tower). There *was* a bad port on the Netonix switch
> it was plugged into, however as with a lightning strike, I wouldn't
> think even a shorted port on the switch would change only that one
> setting - I could see it defaulting the entire radio, but not one
> setting like that.
>
> Anyone ever seen anything like that?
>
> Thanks
> Sam
> ___
> Ubnt_users mailing list
> Ubnt_users@wispa.org
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>



-- 

Adair Winter
VP, Network Operations / Co-Owner
Amarillo Wireless | 806.316.5071
C: 806.231.7180
http://www.amarillowireless.net

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