ixfr-out, document duplicate check for ixfr creation by nsd-checkzone in
the man page for it.
@@ -42,6 +42,9 @@ the zonefile directory. This is also where the result is written, to a file
with the zonefile name, ending with '.ixfr'. This is also where NSD reads it
when IXFRs are configured for the zone. The other existing ixfr files are
renamed to become older IXFR contents for the zone, if any such files exist.
+If the output file already exists with the correct contents, no new file is
+created. The contents of the header of the output file are checked for that,
+if it already exists.
.SH "SEE ALSO"
\fInsd\fR(8), \fInsd-checkconf\fR(8)
.SH "AUTHORS"
