Hi all, i am trying to use DMVPN in my environment. The issue is with nhrp. i have 1 hub and 1 spoke

Hub configuration

int tun 111

ip add 172.27.0.1 255.255.0.0

tun source 10.0.0.1

tun mode gre multipoint

ip nhrp network-id 100

ip nhrp map multicast dynamic

Spoke configuration

int tun 111

ip add 172.27.0.2 255.255.0.0

tun source 20.0.0.1

tun dest 10.0.0.1

ip nhrp network-id 100

ip nhrp nhs 172.27.0.1

My hub and spoke are connected via ISP with 2 /30 subnets on each side. currently i am using normal p2p gre tunnel and everything is working fine, but as soon as i try nhrp, it doesnt work !!, i mean if i do debug nhrp, from spoke i can see packets being sent, but if i do debug on HUB i dont see a single packet of nhrp !!, ISP is claiming that they are not filtering any packets but then why my packets are not being shown on HUB ? my hub is 3845 advseck9 and spoke is 1841 advseck9.

Any help pls ??