D-Link DFL-1600 User Manual page 65

8.2. Services
User-defined IP protocol service
Services that run over IP and perform application/transport layer functions
can be defined by IP protocol numbers. IP can carry data for a number of
different protocols. These protocols are each identified by a unique IP
protocol number specified in a field of the IP header, for example, ICMP,
IGMP, and EGP have protocol numbers 1, 2, and 8 respectively. The
currently assigned IP protocol numbers and references are published on the
web site of Internet Assigned Numbers Authority (IANA):
http://www.iana.org/assignments/protocol-numbers
Similar to TCP/UDP port range described previously, a range of IP
protocol numbers can be used to specify multiple applications for one
service.
Example:
( For more information about GRE, please refer to
WebUI
:
Objects Services
General
Enter the following and then click OK:
Name: GRE
IP Protocol: 47
Adding a service that matches the GRE protocol
Add
D-Link Firewalls User's Guide
22.2 PPTP/L2TP
IP Protocol Service
45
)