list of DHCP options
https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml
Common options
option 3 = router
option 6 = DNS servers
option 15 = domain_name
option 150 = TFTP server
option 128 = PXE - undefined (vendor specific)
Vendor options
some phone systems use their own option for example
nortel use 128 and 191
How to set options
You can set them on the domain controller under DHCP -> Scope -> scope options
Cisco phone registration process
Step 1: Phone Loads Software (Image) and Starts the Configuration Process
Step 2a: Phone Sends DHCP Request
Step 2b: DHCP Server Sends DHCP Response
Step 3a: Phone Sends TFTP Request for a Configuration File
Step 3b: TFTP Server Sends the Default Configuration File
Step 4a: TFTP Server Sends the Specific Configuration File of the Phone
Step 4b: Phone Registration Finishes
Check voice vlan is allow and native vlan matches
Cisco
switchport mode trunk
switchport trunk allowed vlan 102
switchport trunk native vlan 102
3Com on other side
port trunk permit vlan 102 (allowed vlan)
port trunk pvid vlan 102 (native vlan)
No comments:
Post a Comment