I have a DNS server (Ubuntu and BIND) set up on my intranet. Most of the time it works fine but sometimes I can't get to certain subdomains. For example, in the morning foo.our.office might work but bar.our.office won't. Then, later, they'll both work. Then, later, bar.our.office and foo.our.office won't.
If I try to visit these subdomains directly on the DNS server machine, they always work. All the computers in the office are on wired connections, so I don't think it's a connectivity issue.
Any ideas as to what's going on?