Hi

There are multiple way to handle it by using EEM script.

Within eem you can use tracking interface or trigger eem with a syslog message. 

I will past a sample of eem after.

To activate dhcp through eem, there are 2 ways:

- service dhcp / no service dhcp ==> if you're using ip helper-address command, you can't use this solution as service dhcp impact dhcp server and relay feature.

- configure your dhcp pool through eem command.

Tracking interface :

track 1 interface FastEthernet1/0/48 line-protocol

event manager applet DOWN-DHCP

event track 1 state down

action 1.0 cli command "enable"

action 1.1 cli command "conf t"

action 2.0 cli command "ip dhcp exclude x.x.x.x"

action 2.1 cli command "ip dhcp pool TEST"

action 2.1 cli command "Network x.x.x.x x.x.x.x"

action 2.1 cli command "default-rout x.x.x.x"

action 2.1 cli command "dns-server x.x.x.x"

action 3.0 cli command "end"

action 3.1 cli command "wr mem"

action 4.0 syslog priority alerts msg "F1/0/48 is down. DHCP server created"

event manager applet UP-DHCP

event track 1 state up

action 1.0 cli command "enable"

action 1.1 cli command "conf t"

action 2.0 cli command "no ip dhcp exclude x.x.x.x"

action 2.1 cli command "no ip dhcp pool TEST"

action 3.0 cli command "end"

action 3.1 cli command "wr mem"

action 4.0 syslog priority alerts msg "F1/0/48 is up. DHCP server deleted"

with syslog event :

event manager applet DOWN-DHCP

event syslog pattern "Interface FastEthernet1/0/48, changed state to down"

action 1.0 cli command "enable"

action 1.1 cli command "conf t"

action 2.0 cli command "ip dhcp exclude x.x.x.x"

action 2.1 cli command "ip dhcp pool TEST"

action 2.1 cli command "Network x.x.x.x x.x.x.x"

action 2.1 cli command "default-rout x.x.x.x"

action 2.1 cli command "dns-server x.x.x.x"

action 3.0 cli command "end"

action 3.1 cli command "wr mem"

action 4.0 syslog priority alerts msg "F1/0/48 is down. DHCP server created"

event manager applet UP-DHCP

event syslog pattern "Interface FastEthernet1/0/48, changed state to up"
action 1.0 cli command "enable"

action 1.1 cli command "conf t"

action 2.0 cli command "no ip dhcp exclude x.x.x.x"

action 2.1 cli command "no ip dhcp pool TEST"

action 3.0 cli command "end"

action 3.1 cli command "wr mem"

action 4.0 syslog priority alerts msg "F1/0/48 is up. DHCP server deleted"

You need to replace x.x.x.x by real IPs and you can change the dhcp pool name.

The solution I prefer is interface taking.

How this is clear.

Thanks 

PS: Please don't forget to rate and mark as correct answer if this solved your issue