DHCP Vendor Class options

[disturbedone]

Trying to set Vendor Class options so Cisco SPA phones get an option 66 that other devices do not.

Wireshark showed the value for a SPA525G as being "Cisco SPA525G" in ASCII or "43 69 74 6F 20 53 50 41 35 32 35 47" in binary.

* Right click server, select Define Vendor Classes
* Create new class called "Cisco SPA525G phones"
* Add description, and ASCII value of "Cisco SPA525G" (without "")
* Right click server, select Predefined Values, add option 66
* In scope, Configure Options, Advanced tab select "Cisco SPA525G", add option 66 and give value of eg 192.168.1.100

Phones do not appear to get this value and never attempt to download anything from the TFTP server.

Any ideas why?

 

[disturbedone]

UPDATE: packet capture shows response of DHCP server with option code 43 for vendor specific information in DHCP ACK so it's presenting it the phone but....

the capture shows the value being
ASCII B.192.168.100.8.
Bin 42 0e 31 39 32 2e 31 36 38 2e 31 30 30 2e 38 00

Or the full Wireshark field is
Option: (t=43,l=16) Vendor-Specific Information
Option: (43) Vendor-Specific Information
Length: 16
Value: 420e3139322e3136382e3130302e3800

The DHCP option 66 definitely only has 192.168.100.8 so where is this B. coming from? I suspect that's why it's not working but why is it even there?

 

[disturbedone]

UPDATE: tested with just using normal (not Vendor specific) options to allocate Option 66 and get the following in Wireshark

Option: (t=66,l=14) TFTP Server Name
Option: (66) TFTP Server Name
Length: 14
Value: 3139322e3136382e3130302e3800

So why is it presenting it differently when using Vendor Class????

 

[Bas1234]

This might help;

http://www.3cx.com/blog/voip-howto/phone-provisioning-complete-guide/

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It works! Now if only I could remember what I did...

Dain Bramaged
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