How to Configure DHCP for Mitel IP Phones

December 30, 2019

In this busy industry, we’re always striving to automate as many things as possible. When adding a new phone to your existing Mitel phone system, you have a choice of manually programming your network information into the phone, or allowing the phone to pick up settings based on a few custom DHCP options that are simple to configure.

Your Mitel server provides the Mitel IP phones with the latest application firmware and the configuration information that enables the IP phone to be automatically added to the Mitel system. The Mitel server’s address must be provided to the phone as a vendor-specific option. Each network is unique and there are many ways to set up DHCP in your system. This is a generalized guide for setting up the DHCP 156 Option for the IP phones and the 42 Option for accurate time and date information on the phone.

To set up DHCP option 156 for Mitel IP Phones:

  1. Open your DHCP manager.
  2. Locate the subnet that your phones will be pulling IPs from.
  3. Navigate to the scope options and add option 156.
  4. Set the value of option 156 to the following based on your system setup:

If your network utilizes VLANs

In the Data VLAN:

  • Option 156:

ftpservers=< HQ Server IP >,configservers=< HQ Server IP >,layer2tagging=1,vlanid=x

  • With x being your voice VLAN ID

In the Voice VLAN:

  • Option 156:

ftpservers=< HQ Server IP >,configservers=< HQ Server IP >,layer2tagging=1

  • Leave the VLAN ID out

If your network does not utilize VLANs

  1. Option 156:

ftpservers=< HQ Server IP >,configservers=< HQ Server IP >,layer2tagging=1

The ftpservers=< HQ Server IP > parameter is for IP110/210/212k/530/560/560g (MGCP) phones. The configserver= parameter is for the IP400 series phones. It is recommended to use both parameters in your scope to encompass all models of phones. 400 series phones will contact the server and download files using HTTP, not FTP.

If you have a DVS as well in your phone system laying, it is possible to configure two FTP servers for option 156. Each parameter is enclosed in quotes, for example ftpservers=”,″. This would allow you to tell the phones to attempt to download their firmware from a local DVS first, and then try the Headquarters server if the DVS is unavailable.

Setting Scope Option 42

Without a time server, some Mitel phones may display the incorrect date and time. Use Scope Option 42 in the same IP subnets as above to point the Mitel phones to an SNTP (Simple Network Time Protocol) time server. If you do not use an internal NTP server, you can point them to a public time server.

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