Mike,
I've experienced a very similar issue, but slightly different. In the
transition from version 5 to version 6 they made some change to the DHCP
server that prevents it from working with Cisco 3550/3560 switches running
stock DHCP snooping. The switches grab the packets, add option 82 and pass
it on. When the Mikrotik DHCP server responds with an offer packet it
doesn't send subnet/default gateway/dns. If you tell the switches to NOT
use option 82, everything magically starts working. I did a writeup about
it here(http://gregsowell.com/?p=4773)...even include some packet captures
showing the wackyness.
Good luck guys!
Greg
On Wed, Apr 2, 2014 at 8:00 PM, <public-request(a)talk.mikrotik.com.au> wrote:
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> Today's Topics:
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> 1. DHCP bug rOSv6.10 (at least) (Mike Everest)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 2 Apr 2014 14:58:25 +1100
> From: "Mike Everest" <mike(a)duxtel.com>
> To: <public(a)talk.mikrotik.com.au>
> Subject: [MT-AU Public] DHCP bug rOSv6.10 (at least)
> Message-ID: <08fe01cf4e27$cca54cf0$65efe6d0$(a)duxtel.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Folks,
>
>
>
> I have received report of this bug behaviour before, but never seen it
> happen myself, or been able to get any diagnostic at all until this
> afternoon. Thought I would post in case it is useful info!
>
>
>
> This has been reported to us previously as "when customer gets DHCP lease,
> no access to anything is possible. When customer enters static lease,
> everything is good. Reboot router, everything fine again for a while. Then
> stops working"
>
>
>
> Today, I discovered the reason. After some number of leases has been
> issued
> by DHCP server, some number in the vicinity of about 200 leases, new
> leases
> are issued with bad subnet mask, no gateway and no DNS. End result, of
> course, is no connectivity.
>
>
>
> This is apparently just related to number of leases, not actual dhcp server
> - i.e. the problem happens after the same number of leases are formed even
> when there are 3 DHCP servers on 4 different subnetworks, or just one DHCP
> server for all clients.
>
>
>
> Today, I had a chance to work with a fellow who had done some much better
> diagnostic work on a network experiencing essentially the same behaviour -
> he discovered that DHCP becomes broken after some time (or some number of
> leases) in that clients no longer receive netmask, gateway or DNS detail.
> Thus the client picks up IP address only, and a default mask (assume based
> on address 'class') and blank gateway and DNS.
>
>
>
> The routerOS version in place omn that network is 6.10 - we have upgraded
> to
> 6.11 and see if it happens again.
>
>
>
> If so, we'll grab some pcaps of DHCP traffic and report to MT - in the
> meantime, if anyone has experience with this issue too, please post it! ;)
>
>
>
> Cheers, Mike.
>
>
>
>
>
>
>
> ------------------------------
>
> Subject: Digest Footer
>
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> ------------------------------
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> End of Public Digest, Vol 2, Issue 3
> ************************************
>
--
GregSowell.comTheBrothersWISP.com
Thanks for the reply Mike.
I might look at resetting the config at some stage. I went back to V6.10
and so far no problems.
Thanks for setting up this mailing list, I reckon it could be very useful.
Cheers, Dave.
On 31 March 2014 12:00, <public-request(a)talk.mikrotik.com.au> wrote:
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> Today's Topics:
>
> 1. Re: wireless on 6.11 (Mike Everest)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 31 Mar 2014 11:15:40 +1100
> From: "Mike Everest" <mike(a)duxtel.com>
> To: "'MikroTik Australia Public List'" <public(a)talk.mikrotik.com.au>
> Subject: Re: [MT-AU Public] wireless on 6.11
> Message-ID: <027d01cf4c76$59e1dce0$0da596a0$(a)duxtel.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Dave, all,
>
> I am not aware of any specific issue, but I do know that from time-to-time,
> MT wifi can go completely screwy and only recoverable by system reset top
> blank config (sometimes netinstall) and re-install from scratch - use of
> export -> reset -> import is essentially same as configure by hand in these
> cases.
>
> It seems like the internal hardware registers in the wireless chipsets
> somehow get out of sync with the actual configuration as reported to
> routeros.
>
> This same behaviour has been most recently evident on CRS wireless switches
> where there was some bug in v6.5/6.6 that buggered up the switching and
> bridging systems so that they behaved in erratic way similar to what you
> describe. Even upgrade to later routerOS would not fix it without also
> full
> system (blank) reset and reconfigure.
>
> May be worth a try on your 433 in case it is a similar thing?
>
> Cheers!
>
> Mike.
>
> > -----Original Message-----
> > From: Public [mailto:public-bounces@talk.mikrotik.com.au] On Behalf Of
> David
> > Ryan
> > Sent: Saturday, 29 March 2014 10:48 AM
> > To: public(a)talk.mikrotik.com.au
> > Subject: [MT-AU Public] wireless on 6.11
> >
> > Howdy all,
> >
> > just wondering if anyone has seen any wireless issues on V6.11.
> >
> > I upgraded my home router (RB433UAH) on the weekend and have found that I
> > have had to reboot twice over a few days in order to get wireless working
> > again. The clients (tablet, smartphone etc) connect but do not receive an
> IP
> > address.
> >
> > I am guessing it is a wireless issue since my IP phone which is connected
> to the
> > same bridge via cable, appears to be fine and it is also DHCP.
> >
> > Any thoughts.
> >
> > Dave.
> >
> > --
> > David Ryan - 0402 054 426
> > RJS Communications
> > dsryan(a)rjs.com.au
> > MTCNA, MTCWE, MTCRE
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> > Public(a)talk.mikrotik.com.au
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>
>
>
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>
> End of Public Digest, Vol 1, Issue 6
> ************************************
>
--
David Ryan - 0402 054 426
RJS Communications
dsryan(a)rjs.com.au
MTCNA, MTCWE, MTCRE
