I've been confronted to a lot of zerg players only playing zergling rush and it's pretty annoying. I usually play terran and I have a lot off difficulties countering these.
The best thing I found was this build which helped me countering the rush and the next wave until I had enough units to attack and beat him.
What is the best build against a Zerg, keeping the zergling rush in mind ? (feel free to post protoss solution too. The best zerg solution is ... wait for it ... zerglings !)
You have to turtle and block off your entrance. Do not use the strategy in that video. It is horrible.
As a Protoss Diamond player, I usually build my Gateway and Pylon in the entrance. I leave just enough space for a unit to pass by and I build a few Zealots to block off that narrow entrance. I also use stalkers to back up the Zealots and the Sentries to forcefield. From here, I turtle and tech up.
Terran players usually block off their entrance with supply depots (Supply depots can raise and lower for units to pass by) and a Barracks. Then they build a few marines first and then a bunker then they tech.
Remember to always scout too. Another tip is to be prepared for Mutalisks because Zerg players who mass Zerglings usually follow up with Mutalisks afterwards.
Something new players might now be aware of is how to stack scvs. Simply put, take all your scvs and send them to harvest a single mineral patch as the lings approach. When they are very close, attack them so they can all hit at the same time. Also, you might have a marine or 2 depending on the map size so put the marine in that stack as well.
Other strats :
1-Scout with the scv building your first supply depots, you will know where he rushes or not
2-Block your choke, nothing he can do then
3-Dont give up!
Many ling rushers are in fact, poor players so if their rush fails, they are both slowed by their cheap strat and in dire need of ideas about what to do next. So if you've lost a few scvs, nothing is lost, keep the choke blocked and pump scvs
For Terran i think you first need to build a turtle, buildings strategically placed on the ramp to block the zerglings for a decent amount of time for you to build a small M&M army.
Word of caution you need to be accurate for this build to work, any hole in the turtle and it's gg.
i build my supply depot behind the ramp. So the zergling can't go into my basis. you can put the space marines behind the depots. the space marines can attac the zerglings.
For Terran I just wall in regardless of scouting. For any other race, you must scout early, but preferably just late enough to see the rush coming and respond. I main Terran and do some Zerg; if I Zerg rush and Protoss does not scout it it's GG.
Protoss can wall in if they must, the cost of 1 Pylon you will have to destroy is less than the cost of a Ling rush. If Zerg scouts your Ling rush, he responds with a Ling rush and pulling Drones or even building Roaches and microing the Drones to protect the Roaches, if he can get the Roaches out in time.
Essentially, if Zerg scouts your Ling rush you're dead. When I felt like Ling rushing, I try to deny the scout at all cost, so if your opponent is denying scouting at all cost, he's probably going Ling rush.
