If anyone is going to be doing tcpdump work, I have some diffs that make
it handle dhcp reasonably well (as it is currently, it handles bootp OK,
and then just barely recognises that dhcp exists).   I did this a while ago
while debugging a problem with the dhcp client (which was reported back to
the isc dhcp list, rather than here).

On the subject, I'm not sure that ascii conversion of tcpdump output is
worth the code it would consume - even the hex output is really useful only
when you're faced with protocols that tcpdump doesn't understand, and you
want to figure out what's going on the hard way (usually it is easier to
add the relevant decode to tcpdump, which is why the dhcp mods got made...)

Once you get past the protocol headers and into the data, you're generally
going to be much better off with something designed for debugging the
particular protocol of concern, than just looking at ascii flying past.

kre