dnsjava IXFR fails if the serial number has rolled over on the server

[<Ale...@us...>]

I am seeing an issue where an IXFR using dnsjava's IXFR client will fail if the serial number on the server has rolled over since the last serial on the client.

So for example, if I am running a DNS server with a serial number for example.com of 4294967295 and then send it an update so that the serial number rolls over to 1. Then I call dnsjava's:
 
ZoneTransferIn transfer = ZoneTransferIn.newIXFR( new Name( "example.com" ), 4294967295, true, "127.0.0.1", null);
transfer.run();

the transfer fails.

If I modify ZoneTransferIn.java and change the line in the parseRR method from:

if (qtype == Type.IXFR && end_serial <= ixfr_serial) {

to instead be:

if (qtype == Type.IXFR && (Serial.compare(end_serial, ixfr_serial) <= 0 )) {

then everything works great and the IXFR completes successfully. Note that I ran into this with the 1.6.4 release, but I did take a look at the code in 2.1.0 and the bug seems to still be there. Let me know if that appears to be a reasonable fix.

Thanks.

---Alexis MacFarlane