When plugging in a Mitel IP phone (5312, 5320, 5330, 5340, 5360, etc) the
first thing it does is try to get an IP address so it can communicate on the network. Option 128 is a Mitel legacy
option that tells the phones where the Mitel 3300 PBX lives. Typically it would read something like 192.168.1.2
Option 128 has been superseded by option 125 and now only exist to provide backward
compatibility with legacy Mitel telephones.
What to do if you see “Option 128 Missing” when booting a
telephone.
First of all, be sure that you have option 125 enabled. This
tells the Mitel telephone the following things:
TFTP Server Address (sw_tftp) – usually the Mitel 3300 ICP
Call Server Address (call_srv) – This is the IP address of the Mitel 3300 ICP
VLAN ID (vlan) – The VLAN that the Mitel telephones will be using
If you are sure that Option 128 is correct and you still get the “Option 128
Missing” error it could mean a couple of things.
The Mitel telephone's boot ROM is out of date and doesn't understand Option 125.
There is an error in the config of the ethernet interface of the DHCP server.
There is a rouge DHCP server on your network.
What to do if your Boot ROM is out of date:
This is one of the simplest things to correct. The answer is to
upgrade the boot ROM. To do this, simply hold the '7' key while booting the phone. It will ask you if you want to
configure Teleworker (TW) mode. Say yes and enter the IP address of your Mitel 3300 IPC PBX. Save the change and
allow the phone to boot. Doing this bypasses option 125/128 and will use what ever IP address is handed out first.
The phone will upgrade it's Boot ROM. Once the phone has upgraded, reset the phone again while holding the '7' key
and delete the option. The phone should not boot up using options 125/128.
What to if there is an
error in the config of the DHCP server Ethernet interface.
This can more difficult to resolve unless you're comfortable
with working with your data switches. Here's what happens normally when the phone boots:
The phone request an IP address. - The DHCP server Offers one.
It accepts briefly the DHCP address.
The telephone reads option 125 (or option 128-131). These options tell the phone
which VLAN it should be on.
The phone releases it's IP address, switches to the appropriate VLAN and request
another DHCP address.
The DHCP server that is handing out addresses for the voice VLAN (frequently the
Mitel 3300 PBX) offers an IP address on the voice VLAN.
The phone accepts it and then boots using the 3300 as it's TFTP server.
However, if the Ethernet interface address in not configured properly for the DHCP
server, it will cause a boot failure.
If the data switch port the DHCP server is connected to is programmed as a “Trunk
Port”, the DHCP server will offer an IP address for both the data VLAN and the voice VLAN. The first server to
respond the the DHCP request wins.
Here's what happens in this situation:
The phone request an IP address. - The DHCP server Offers one.
It accepts briefly the DHCP address.
The telephone reads option 125 (or option 128-131). These options tell the phone
which VLAN it should be on.
The phone releases it's IP address, switches to the appropriate VLAN and request
another DHCP address.
The Mitel 3300 offers a DHCP address.
The DHCP server on the native VLAN also responds with anther IP address.
If the DHCP server on the native VLAN responds before the Mitel 3300, the
telephone will not be able to talk to the 3300 because it has a data VLAN IP address on the Voice VLAN.
The phone will eventually time out and reboot – repeating the process.
The solution is to reconfigure the data switch port connected to the DHCP
server on the native VLAN so that it is configured to be an “access” port or “untagged”. This will ensure that the
DHCP server does not see the second DHCP request from the Mitel telephone.
What To Do If You Have a Rouge DHCP Server On Your Network
It happens. Someone in your office bring in a wireless router so that they can use a
wireless device at work. This device is now handing out DHCP address on your network. A rouge DHCP server can
break a network and stop a Mitel telephone from booting giving the “Option 128 Missing” error.
This can be very difficult to trouble shoot. In this case I would recommend that you
engage some serious help. But, in order to help out at least a little bit, here's what I've been able to do when
this has happened:
Using my laptop I request a DHCP address.
I then entered the command “ipconfig/all” from a DOS prompt.
The results will show the IP address of the DHCP server that handed out the
address.
Next, from the DOS prompt again I enter the command “arp -a”. This will show you
the MAC address of the DHCP server.
Next I entered the 1st thress octets of the MAC address – (i.e.
00:04:5A will show Linksys)
Then I at least knew what I was looking for and began my hunt for the rouge
server. (Note: Turns out that this was a collage student who wanted to use his iPod Touch at work.)
I admit that seeing a rouge DHCP server is pretty rare but at least you should be
aware of the possibilities.
Rouge DHCP - everyones bane! Anyway, an old XP resource kit tool
called dhcploc.exe will send out a DHCP request and show you all replies. It actually shows all DHCP traffic it
sees. VERY handy.
With info from dhcploc and most managed switches you can track the culprit down to a port. Switch syntax
varies, but the gist is using the mac address and arp tables to figure out what port the culprit is on....
-Chak
If You've found this advice helpful, please consider a
donation to help keep this type of assistance on-line and available.
Please join our forum and follow our
newsletter. Your participation may help others.