My own hassles with DNS, some of which are mentioned.
1. windows and apache httpd and others cache things
for a long time, seemingly forever.
2. The 'A' record is used in case of missing MX records. Who knew that?
3. (in the olden days) confusion with winbios and other naming schemes
4. The defn of 'authoritative'
5. the misleading semantics of 'domain' in resolv.conf
6. (minor) the casual use of CNAME to mean alias, whereas it fact
means the opposite and is used to refer to the record, not the name.
7. That DNS can use tcp/53. The number of misconfigured firewalls I've
dealt with argh.
8. Split vs forwarding DNS. e.g. impact on the .dev
domain.
9. The urge of some to put underscores in their names.
I believe that some (early?) implementations allowed
them.
10. Someone putting in a lower 'serial' in named.conf and
the struggle to restore sanity.
DNS's caching behaviour in the wild is incredibly infuriating. We have one team member at my company who is stuck with a stale DNS record for one of our internal services in our application, but their browser works just fine. I've absolutely no idea how to actually fix it, so for that one persons benefit we bought a whole new domain and ported everything to that.
Split DNS has let us do some cool things, and simultaneously caused no end of headaches. See above for the sorts of headaches.
