-.Xr ifconfig 4 ,
-followed in all cases by a colon and
-an interface address in the form of
-groups of hexadecimal digits
-separated by periods.
-Each group represents a byte of address;
-address bytes are filled left to right from
-low order bytes through high order bytes.
+.Xr ifconfig 4 )
+followed by a colon when the interface identifier is present,
+followed in all cases by a sequence of hexadecimal
+.Dq digits
+(optionally separated by periods),
+of the form:
+.Bd -filled -offset indent
+<name unit :> <hex digits>.<hex digits>.<hex digits>
+.Ed
+.Pp
+Each pair of hexadecimal digits represents a byte
+with the leading digit indicating the higher-ordered bits.
+A period following an even number of bytes has no
+effect (but may be used to increase legitibility).
+A period following an odd number of bytes has the
+effective of filling the byte of address being translated
+to have its higher order bits filled with zeros.