de_dust2 is one of the most popular bomb defusion maps in Counter-Strike: Source. It is set in the Middle-East, and has the two teams start on opposite sides of the map, the counter-terrorists quite close to both bomb sites, and the terrorists not too much further away.
The terrorists start at the top end of the map, far away from both bomb sites. To their right is the pair of doors which provide a long-standing battle with any counter-terrorists moving that way ("long A"), to their left is a hall which also provides long and grenade-filled battles (leading to bomb site B), and forward is the main ramp, which is a good point for attack. If there are any snipers on the terrorist team they should stay at spawn for the first few seconds of the game, as it is possible to snipe down any advancing counter-terrorists through the tunnel, down the ramp and through the doors at the bottom.
A small group should always defend the double-doors on the right from any advancing counter-terrorists, as if any get through, they can sweep round behind the other terrorists and kill them. Throwing flashbangs and frag grenades into the double-door area is a highly effective tactic.
Another group should go left and tackle any counter-terrorists at bomb site B. Again, grenades help - especially if the counter-terrorists already hold the hall - but a sniper rifle is also useful if any counter-terrorists are camping behind the crates in the bomb site B area. If this area can be cleared fast enough, and the bomb carrier is with the group, the bomb should be planted at bomb site B as soon as possible, and a defense mounted. When in the tunnel, do not relax your guard as sometimes counter-terrorists rush through the double doors and enter the tunnel from the right. When this happens it can be devastating to your assault on bombsite B. However, the tunnel exit on your right can also be used to your advantage, as it leads to the big double door, which is a popular camping spot for counter-terrorist snipers. If you go down the tunnel on the right hand side it is possible to take these campers by surprise, killing them, and then proceeding to one of the bombsites (B to the left, A to the right). This can take counter-terrorists by surprise as they will probably be focusing on defending attacks coming from other directions.
The remaining players (usually half of the team) should go down the centre of the map and attack the entrance to bombsite A which is on their right ("short a") and taking on any counter-terrorists at bomb site A. Although, be prepared to fight some counter-terrorists en-route, as counter-terrorists on the other side of the double door might fight you, and you may run into some counter-terrorists leaving bombsite A through A short. Grenades are very useful here. If the bomb carrier is with this group, the bomb should be planted as early as possible at bomb site A, and a defense should be mounted again. expect attacks from any direction at this stage.
The counter-terrorists have a convenient position, starting near both bomb sites. However, most counter-terrorists completely disregard this, and go out hunting the terrorists.
To the right of the spawn point is the double-door, which is highly dangerous. It is sometimes a good idea for snipers to position themselves here, or the terrorists will break through and cut the counter-terrorists up from behind. Flashbangs, smoke grenades, frag grenades and lots of patient waiting will probably be needed to gain a victory at the double-doors, but be warned that the terrorist team will most likely be doing the same, and somebody will have to break the stalemate at some point. It is possible to gain access to the tunnel from the double doors, and take unsuspecting terrorists by surprise. The tunnel is past the double doors and to the right, it will likely require flashbangs or smoke grenades to get to the tunnel past terrorist snipers. It is ill-advised to rush straight up the centre of the map from here, as the terrorists have a straight line of sight from their spawn down through the doors, and any snipers will cut adventurous counter-terrorists down.
To the left of the spawn point is bomb site A. One of the exits from it, known as "A short" leads down some stairs to the middle of the map. This is to the right of bombsite A, if you are looking towards the terrorist starting point. A small group of players rushing this route with flashbangs can be tactically beneficial, however it should be expected that the terrorists will try the same thing, so if you plan to use this tactic, prepare for a close range fight. Once any terrorists in the centre of the map are neutralised, the counter-terrorists have the choice of where they go. Two good choices are the tunnel leading to bombsite B (this is next to the double door) or the corridor leading to bombsite A (head towards the terrorist's spawn point then enter the doors on your left), shooting any terrorists in the back: this strategy is especially useful if it's early on in the game.
To the right of the counter-terrorist spawn point is bomb site B, where they can engage the terrorists in the tunnel. Usually, the counter-terrorists will get into the hall first, but in any case, flashbangs and frag grenades should be used extensively. A smoke grenade at the counter-terrorist end of the tunnel is quite useful if it is occupied by terrorists. Counter-terrorists should do their best to prevent the terrorists from planting a bomb here, as bombsite B can be difficult to assault if it is well guarded.
Bomb site A.
Bomb site B.