cisco-pnp

pnp server discovery

There are 3 main way for the device to discover the ztp server:

1. DHCP Option 43: I hate with passion because the documentation isn't super clear and I'm using it for AP discovery, therefore I didn't tested it
2. DNS: The device will look for pnpserver.localdomain, I like this one better and it is what I ended up using
3. Cloud redirect: couldn't test it because my lab sits behind a proxy

DNS discovery configuration

This is the DHCP configuration needed, note the DNS server and the local domain.

ip dhcp pool Vlan1
 network 10.102.1.0 255.255.255.0
 default-router 10.102.1.1
 dns-server 10.102.2.20
 domain-name secmob.local

(and remember to create an entry on the DNS server!!)

Gotchas

1- The out of band management interface in cat3650 and cat3850 doensn't work properly:

• Before everest - 16.5.1a - no discovery at all is done using that interface
• in 16.5.1a the interface will be down after the pnp operation

interface GigabitEthernet0/0
 vrf forwarding Mgmt-vrf
 ip address 10.102.1.48 255.255.255.0
 negotiation auto
 shutdown

I have tried to force the no shutdown on the configuration, but this in turn made the pnp process fail AND shutted down the port anyway - investigations in process

2- In 16.5.1a weird behaviours are observed if the configuration for the port used for pnp is not in switchport

In my case this is the intended configuration:

interface GigabitEthernet1/0/37
 no switchport
 ip address 10.102.1.11 255.255.255.0

And this is the outcome:

interface GigabitEthernet1/0/37
 no switchport
 no ip address

Workaround: use switcport and move the ip to the vlan.