"Using IP Service Object in Firewall Builder
In Firewall Builder, service objects represent IP, ICMP, TCP, and
UDP services such as "host unreachable" in ICMP, HTTP in TCP, GRE
in IP, or DNS in UDP. Firewall Builder provides service objects for
over a hundred of well-known and frequently used services in ICMP
(IP protocol number 1), TCP (IP protocol number 6), and UDP (IP
protocol number 17).
The IP service object describes protocols that are not ICMP, TCP,
or UDP. (ICMP, TCP, and UDP have their own service objects.) An IP
protocol is defined by the 8-bit field in the IP packet header. The
screenshot below represents the ESP object (Encapsulating Security
Payload, part of the IPSEC protocol family) which uses the IP
protocol number 50"