I've done my best to google and my foo is not strong it seems.
I have a mikrotik router, I've setup my VLANs properly and DHCP portions. I've added my DHCP option, and added to the 'network'.
Using wireshark and the log on the router.. When a phone makes a DHCP request, I see that the DHCP server on the default vlan is responding and is sending the option 132 and the hex value, but I don't see the phone doing anything with it, even though DHCP vlan is enabled.
I've tested this on both Htek and Yealink phones, and still no joy.
Any suggestions?
6 comments
I was fortunate enough to work on a case where my customer wanted to employ Option 43 to work with DHCP Server for Windows Server 2003. His Access points needed this option to be configured on the servers so as to receive the specific scope options (such as the WLC IP address, Static Routes, etc). These options are only specific to the access point devices, and hence- we wouldn’t want all the other clients to receive them. That’s why, we need to configure Option 43 to ensure that only that Vendor Specific class would receive that set of options.
Option 43 This option is used by clients and servers to exchange vendor-specific information. Servers that are not equipped to interpret the information ignore it. Clients that expect but don't receive the information attempt to operate without it.
Option 60 It can be used by DHCP clients to identify their vendor type and configuration when communicating with DHCP servers. Vendors can define their own specific identifier values, like conveying a particular hardware or operating system configuration.
When configuring Option 43, we should also configure Option 60.
Option 60 is the 'Client Identifier'
What is that?
When a regular DHCP client tries to get an IP, it just goes for a regular broadcast asking for an IP address, and scope options like Router, DNS server, etc. However, other clients like Access Points, scanners, printers, etc have to identify themselves and ask for a specific option from the DHCP server. So we need to configure this option 60 packed with Option 43. Option 60 is where we give clients the ability to “Identify” themselves to receive the proper scope options from the DHCP server (specific to the Vendor)
On a Microsoft DHCP server, it's a 3 step process:
Yealink Windows Dhcp 43 Example Pdf
1) Define the Vendor Class
2) Configure the Predefined Option
3) Configure the Values for that specific scope.
In my example below, the “Default Scope Options” are already defined.
Yealink Windows Dhcp 43 Example For Sale
Defining the Vendor Class
Right click on the DHCP server > Define Vendor Classes.
Create 'Add' > New class > Define the Display name and Description
In ASCII, you enter the details of the access point there: Cisco AP c<model number>
This converts to Binary
2) Configure the Predefined Option
So now that we defined the identifier on DHCP Server, we need to configure this identifier option to send the WLC IP address back to this client. Right click > Go to “PREDEFINED OPTIONS
This is where we configure what IP address (or other information) to provide to the client, depending on what 'Code' we configure here.
Here, the code '241' is used for returning the value of the 'WLC Control Management IP' back to the client. This is a known setting.
This will take us back to the previous screen:
]
Do not enter the array of IP's here, since we need to define the IP Scope option specific to the scope and not make this a global setting.
3) Configure the Values for that specific scope.
This is where we go to the scope to define the IP address of the WLC controller, and we click on 'Configure Options'
This is where we will need to define what is the IP of the WLC, which can be supplied to the client from that specific scope. This way, we can setup a different WLC for every different scope.
We have successfully configured the Server to identify Client Option 43, coupled with Option 60 to ensure that the vendor specific clients get the right options from Windows DHCP server.
You may contact the vendors themselves for the correct values to specify under the 'Predefined Options' for the respective devices.
Please feel free to comment below; Happy Discovering 🙂
Article by Nikhil Mehta Support Engineer - Platforms Networking
When trying to auto provision Yealink phones, sometimes users cannot get devices to download the configuration files from server using DHCP option 66. Here are the original words from user:
“Customer has T28 phones, newest version. He has a Windows server and is trying to use option 66 to provision the phones automatically. Using wireshark he can see that the windows server is communicating with the phone and is offering the option 66 string but the phone is not auto populating the provisioning server field. “
The most probably reason is that the server is not trusted by Yealink phones. Here is the authentication logic on Yealink phones:
1.DHCP Server sends auto provision server URL to YL phones.
2.Phone turns to URL to request for provisioning files.
3.If HTTPS server is used, phone will first check whether the server is trusted or not by comparing the certificate applied on server and those pre-installed on phone. If the server is trusted phone download configuration files and get provisioned.
4.If the server is not trusted, phone will check the value of “Only accept trusted certificate” itself. If value=1, ends configuration process. If value=0, phone will ask for configuration file regardless of the certificate result.
The pre-installed certificates on Yealink phones are listed on page 268-269 of Administrator Guide (apply to all phone models) below: Yealink_SIP-T2_Series_T4_Series_T5_Series_CP920_IP_Phones_Administrator_Guide_V84_12.pdf
For more information about auto provision, please refer to:
For further support, please contact Yealink FAE by emailing to ticket.yealink.com.
I can only give you part of the picture. DHCP option 66 and Asterisk have nothing to do with each other.
From the sounds of it you are using Elastix (good). Elastix is based on the Centos operating system. The target of DHCP option 66 should be your Elastix server. Under centos you have the tftp service loaded. Tftp is the service referenced by DHCP option 66 (and 67 but that's not used for phone provisioning). To serve files via tftp the files must be loaded in the /tftpboot folder on the Elastix server. Usually (but not always) phone configuration files have two parts. One is a common configuration file for all phones of the same manufacturer. The second configuration file is usually named the mac address of the phone. This is where phone specific settings are stored.
I haven't personally used Yealink phones, but there are other in the community who do (NetworkNerd and SAM). They should be able to fill in that part.
I can only give you part of the picture. DHCP option 66 and Asterisk have nothing to do with each other.
From the sounds of it you are using Elastix (good). Elastix is based on the Centos operating system. The target of DHCP option 66 should be your Elastix server. Under centos you have the tftp service loaded. Tftp is the service referenced by DHCP option 66 (and 67 but that's not used for phone provisioning). To serve files via tftp the files must be loaded in the /tftpboot folder on the Elastix server. Usually (but not always) phone configuration files have two parts. One is a common configuration file for all phones of the same manufacturer. The second configuration file is usually named the mac address of the phone. This is where phone specific settings are stored.
I haven't personally used Yealink phones, but there are other in the community who do (NetworkNerd and SAM). They should be able to fill in that part.