I think it make sense for ipsec.4 to reference it's own configuration file under SEE ALSO.
Index: ipsec.4 =================================================================== RCS file: /cvs/src/share/man/man4/ipsec.4,v retrieving revision 1.83 diff -u -p -r1.83 ipsec.4 --- ipsec.4 16 Feb 2015 16:38:54 -0000 1.83 +++ ipsec.4 18 Mar 2016 20:51:05 -0000 @@ -378,6 +378,7 @@ allocations). .\".Xr ipcomp 4 , .Xr options 4 , .Xr iked 8 , +.Xr ipsec.conf 5 , .Xr ipsecctl 8 , .Xr isakmpd 8 , .Xr sysctl 8
