SSH From iMac Won't Always Work With Abbreviated Names

Question

I've been using my iMac for a few weeks without any problems, but today, I'm running into a strange one. I had to change the DNS from one computer to another, both running on Debian Linux (old one was Debian Etch, new is on Debian Lenny). The older computer is now offline. I'm using the same DNS server I was using before and the same config files, which I've checked over before copying them. I've never had a problem like this before.
My LAN, just for reference, uses character names from Oz for the computers (suggested by a young relative!), so the domain name is thresh.oz, my iMac is polychrome or polychrome.thresh.oz, and the computer I'm trying to reach, which is running Debian Etch, is scarecrow or scarecrow.thresh.oz.
I had this problem earlier when I tried to ssh to the new DNS server, but it disappeared after a reboot. The current problem system, scarecrow, is running software for business doing searches and I really do NOT want to reboot it until later this week -- so I'd like to solve this without reboots.
With this computer, when I type "ssh scarecrow" I get this error message:
ssh: Could not resolve hostname scarecrow: nodename nor servname provided, or not known
If I use "ssh -vvv scarecrow," I get this:
OpenSSH_5.1p1, OpenSSL 0.9.7l 28 Sep 2006
debug1: Reading configuration data /etc/ssh_config
debug2: ssh_connect: needpriv 0
ssh: Could not resolve hostname scarecrow: nodename nor servname provided, or not known
If I type "ssh scarecrow.thresh.oz" or "ssh 172.16.7.4" I get a connection without a problem. I've specified in my DNS config file (it's DNSMasq and the info is read from /etc/hosts on the DNS server) to recognize the computer as scarecrow or scarecrow.thresh.oz. On my Linux computers I've specified to always use "thresh.oz" as the search domain (not sure how to do that on my iMac).
I have a number of scripts that refer to this system only as "scarecrow" without the domain name and without an IP address and I don't want to have to change them.
I can deal with this for now and reboot later, if that's what makes a difference, but it's a major pain and I hate the idea that I might have to deal with this in the future and be forced into reboots.
I did find this thread:
http://discussions.apple.com/thread.jspa?threadID=1524974
But the solution wouldn't fit here, since a character was mistyped from cut & paste and in my case I'm simply typing "ssh scarecrow."
Any ideas on this?
Thank you!

Answer 1

I should have elaborated more. Part of it is I'm still getting used to where things are on a Mac compared to Linux. I checked preferences and do have thresh.oz in there. I can type "ssh wizard" and it works or "ssh ozma" and it works (although it didn't earlier, before I rebooted ozma, which is the DNS server here), but typing "ssh scarecrow" would always give me that same error message.
In other words, the problem was ONLY with ssh'ing to that one system and only with the name "scarecrow," not with "scarecrow.thresh.oz," but there was no need for the full domain with other systems.
I was thinking in terms of the reboot with the DNS and how that could have fixed it -- is there also any kind of cache the iMac would keep -- a lookup cache or something like along that line that would get renewed over time that might have fixed it instead of the reboot I did?