I'm pretty sure this is not a dhcpcd problem, but thought I would ask in here before banging my head against the wall again.
I have a Pi2, which has a hostname of "devbox". I use this at home, and occasionally at work (since it has my media player on it).
When at work, the dhcp server in use is the Windows 2012 one. Having ticked the relevant boxes to have the sever update DNS, it is all sweetness and light, and I can ping using the hostname.
However, at home, I have Windows Server 2008R2. Having configured the DHCP server therein in the same way, I cannot use the hostname.
Before kicking the Windows DHCP and DNS servers into touch, I examined the DHCP lease properties, and it appears that the DHCP server is trying to use the hostname byte sequence 0x06 0x64 0x65 0x76 0x6f 0x78. In other words, it is treating the length byte as part of the name.
Any ideas why this might be the case? The DNS server is then rejecting the attempt to update the A or PTR records, on the grounds that it's a bad name, of course.