I see way too many people who think the single quality defining a tank is
a high armor value, and that enemies will magically start attacking the
tank just because of that. Tanking is a skill useful not only in dungeons,
but whenever a group of players are fighting a group of enemies.

Your sole purpose as a tank is to keep enemies away from casters, and most
importantly, healers. A good healer can keep you alive almost no matter
how much damage you take, as long as they are free to cast uninterupted.
Non-caster players will generally be ok on their own, since they only
aggro the single units they are attacking, but allways keep an eye on
everyone just in case.


Main tank: The reason why you need a main tank for a dungeon is that when
fighting single targets (bosses), there is no tactic a dmg-dealer can use
to reduce the amount of aggro he produces (except to stop attacking). You
simply need someone who can out-aggro anyone, with high enough armor to
make healing effective. Also, if a healer is being mobbed, and is forced
to start healing himself excessively, it can create an aggro lock that is
almost impossible for anyone but a really good tank to break.

Off-tank: The defenition of an off-tank is a player that can safely and
effectively tank one enemy. Depending on the situation and composition of
your group, this may apply to anything from paladins to rogues or
range-spec hunters. Basically, if you are fighting more units than the
main tank can handle (damage- or aggro-wise), an off-tank needs to step
in. As stated in the tips and tricks below, try to go for a target that
isn't being attacked, it will be much easier for you to pull, and you will
not need to attack it continuously to keep it locked on you.



General main tank requirements: There are only two really good tank
classes, warrior (defensive stance) and druid (bear form), with paladin as
the third "ok" tank, viable in dungeons up to lvl 35 or so. But in lack of
these, any fighter class can go in as emergency tank, provided the enemies
are weak enough for him to handle (don't try this in dungeons!). Equipment
and talents matter a lot naturally, so for any situation that requires a
good tank, don't go with caster-specced druids or warriors without shield.

High level dungeon main tank requirements: Forget paladin, and don't use a
druid if you can help it. Good feral druids are rare, and even they are
generally more valuable as healers. Warriors (with shields) have superior
final armor and hit points, and is the only real choise. Points in
tactical mastery is almost a must, it enables the warrior to use the best
of different stances.



General tips and tricks:

* Some abilities generate more aggro than others. There's no table of
statistics that I know of, but you can figure it out roughly on your own.
It might allso be a good idea to use low aggro abilities when you aren't
tank.
* Leave to others what they can handle themselves. For example, if a mage
is attacked by a single enemy and you aren't close, he will cast
polymorph. If you charge in, you might leave other players vulnerable for
no use.
* Enemies that aren't being attacked are very easy to pull, a single hit
or spell can make them turn on you.
* Since the enemies will be following you, you are responsible for making
sure they take maximum damage from aoe spells.


Tanking with warrior/druid:

Taunt is your main weapon, it almost always pulls the targeted enemy.
Sunder armor and fiery fire are rage/aggro-effective abilities, so spam
away, and save bash/disarm to disable units you don't have time to pull.
The hp loss from berserker rage (warrior) is minimal, but be careful about
enrage (druid), the -25% armor is not helpful in a serious fight. Feral
charge (druid) is a highly useful ability for intercepting enemies that
are running away or attacking casters.


Tanking with paladin:

Using Seal of fury, and having cast blessing of salvation on everyone you
think needs it, you can pull a resonable amount of aggro, but accept your
limits and stick to protecting the casters first of all. Save hammer of
justice to disable units you don't have time to pull, and use blessing of
protection wisely. Improved seal of fury allows you to tank slighly
better, but you still wont be able to tank in dungeons past level 40,
unless you are at a significantly higher level.



Things to stress to your teammates:

* Spread out a little, if you stand in a pile I can't see who's being
attacked.
* Don't overnuke! If you are being attacked, switch target or stop
attacking. (to casters)
* Don't cast spells, just heal! (high level healers will generally know
when to do which)
* If you're being attacked, run towards me, that way I can get the unit
off you easier.