DNS-based host name lookups can be what I'll call 'relative', whichlook for the host name inside some domain, or 'absolute', whichassumes that the host name is fully qualified and starts right fromthe root DNS. (For clarity, absolute names are often written with atrailing '.'; this can often be used to make resolver libraries treatthem as absolute.)

Once upon a time, we had an interesting mail explosion. The campuswide mail servers started sending our

One of the things I write in Python is network daemons. Because it worksso nicely, network daemons usually take input as text lines that startwith a command word and have whitespace separated arguments. There'sa certain amount of eye-rolling tedium in writing code to check thatthe command word is valid and has the right number of arguments. WhenI wrote a program that does a lot of this, the tedium finally got tome and I sort of snapped and automated all of the validation throughPython'

I just helped a friend troubleshoot a DNS problem he was having on oneof his home Linux machines. The specific problem was that Firefox wastaking a long time to start connecting to web sites; he believed itwas DNS problems.

I ran down some standard guesses:

• maybe one or more nameservers in /etc/resolv.conf weren'tresponding, and Firefox was having to wait for lookups against eachto time out. But straight lookups with dig weren't delayed, so itwasn't that.