tunnel-end-point name {
ipv4 {
source-address 10.255.1.1;
destination-address 10.255.2.0/25;
}
gre {
key 9;
}
}
https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/ref/statement/tunnel-end-point-edit-firewall.html The ip and gr interface types are used as endpoints for various tunneling protocols. ip is a generic term that can refer to any IP-based tunnel, while gr specifically refers to Generic Routing Encapsulation (GRE) tunnel interfaces in Junos.
Reference:
Juniper Networks documentation on Interface Types: Interface Types and Their Default Properties