.Bk -words
.Op Fl l Ar logfile
.Ek
-.Bk -words
-.Op Fl P Ar isakmp-natt-port
-.Ek
-.Bk -words
-.Op Fl p Ar isakmp-port
-.Ek
.\"
.Sh DESCRIPTION
.Nm
+is used to setup and maintain an IPSec tunnel or transport channel,
+between two devices, over which network traffic is conveyed securely.
+This security is made possible by cryptographic keys and operations
+on both devices.
+.\"
+.Nm
+relies on a standardized network protocol (IKE) to automatically
+negotiate and manage the cryptographic keys (e.g. security
+associations) that are necessary for the
+IPSec tunnel or transport channel to function.
+.\"
+.Nm
speaks the IKE
.Pq ISAKMP/Oakley
key management protocol,
.Ar logfile
as the logging file instead of
.Xr syslogd 8 .
-.It Fl P Ar isakmp-natt-port
-Use
-.Ar isakmp-natt-port
-for NAT-Traversal port-floating.
-The default is 4500.
-.It Fl p Ar isakmp-port
-Listen to the ISAKMP key exchange on port
-.Ar isakmp-port
-instead of the default port number, 500.
.It Fl v
This flag causes the packet dump be more verbose, with higher
debugging level.