Mitel 53xx phone stuck in DHCP Discovery mode

Posted on 2011-04-25
Last Modified: 2012-05-11
I am trying to install a Mitel phone ( believe it is the 5320) but it is stuck in DHCP discovery mode.

The user is a consumer and is getting their internet services from a Cable Modem (Videotron). The internet is working fine.

I have done the following:
   - switched routers (no impact)
   - removed the router (no impact)
   - tried powering it with a PoE brick and with a Cisco switch (no impact)

One weird thing that happens is when a desktop PC and the phone are connected to 2 LAN ports in the same router, when the phone is plugged in and goes into DHCP discovery mode, the desktop PC loses almost all connectivity with the internet.

I am stumped, and I need some help to understand how to further diagnose and fix the problem.

Thanks, Peter
Question by:pbissegger
    LVL 20

    Expert Comment

    What type of switch ? Maker and Model number would be good.

    I'm assuming the cat5 cables are good and you have tried swapping them about and maybe testing other cables.

    I'm assuming you have DHCP enabled on the system and it has free valid address.
    I am assuming it is set up with the right subnet, default gateway and DNS servers etc.

    I am assuming you have the phone setup right to do SIP not standard local mitel connection and your phone system is setup to allow incoming SIP (maybe you have tested this elsewhere).

    Let me know if any of my assumptions are wrong :)

    Author Comment


    To answer a few of your questions:

    DHCP is enabled on the system and it has free valid addresses. The other computer has received its IP address from the DHCP server. We also tried fixed mapping the IP address to the Telephone MAC address to no avail.

    Since the other computer is working perfectly, I assume that the subnet, default gateway and DNS servers are fine.

    I will get back to you with the make and model of switch....

    I have a question - how can I tell whether the phone is setup to do SIP or standard Mitel connection ? Its supposed to be configured for SIP, and I have installed 3 other SIP phones which have connected properly to the phone system - so this should be OK.

    Good idea for the cables, I will ask them to switch them and ensure this is not the issue....

    I will get back to you,

    Thanks, Peter
    LVL 20

    Expert Comment

    press the grey/blue key and go through the menu until you get to 'admin menu' and then under that, network settings.
    Its somewhere in there.   Sorry for being a bit vague - I've never used one as SIP.
    You could also try the docs :
    LVL 3

    Accepted Solution

    As a shortcut, you can hold * and 7 during the boot to put the phone in SIP mode or * and 6 to return it to the default  Minet mode.

    Mitel Phones, if they are connecting directly to the Mitel controller need option 125 configured in DHCP.
    If they are connecting via a teleworker solution, then they need the IP address of the teleworker server programmed on the phone (static)

    I would hazard a guess that the DHCP scope doesn't have the Mitel option (125) configured and so the phone will reject any offers made to it.

    Author Closing Comment

    Sorry for the delay. Yes, this seems to be exactly the problem that had occurred.

    Thanks !

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