DHCP options

[sgalarza]

I'm trying to figure out if the options in our dhcp pool are needed or not.  We have an NTP server command in our configuration but I'm just wondering if we even need these options in our pool.  Here is the configuration for one of our pools.  We do use the option 156 for our ShoreTel network, but the other ones I'm not sure of, thanks.

ip dhcp pool AP-USERS
network 10.0.17.0 255.255.255.0
default-router 10.0.17.1
dns-server 10.0.1.99 10.0.50.11 10.0.13.5
option 43 hex f104.0a00.01eb
option 4 ip 10.0.1.99
option 42 ip 10.1.1.20
option 156 ascii "ftpservers=10.1.1.20,layer2tagging=1,vlanid=200"

[Philip D'Ath]

Option 156 is definitely used.
https://support.shoretel.com/kb/view.php?id=kA21A000000LTX8SAO

Option 42 is used by the phones to tell them where to get time from.

I've seen option 43 used with other phone systems (Avaya I think).  I don't know if ShoreTel uses this.  I haven't seen option 4 used before.

[sgalarza]

Philip,

I forgot to mention, this is our Data Vlan, our Phone Vlan doesn't use option 42, but does use option 4.  I've researched these options, but I'm not sure how they all work together.

Thanks