[b]** Update **

Just wanted to update everyone on the situation here.
If you need help dealing with denial of service attacks, please contact me directly via Twitch.TV message to misterslin. Alternatively you can contact me at twitter.com/misterslin. Do not contact me on Steam.

I have a lot of information about our attackers. Yes, there are multiple people involved. For now, I will keep their names private. What you do need to know is that they are amateurs. They have purchased software online that allows them to do this. Most of the attacks come from a single IP address, and it is a very unsophisticated attack. If you have any sort of IP flood detection or ability to redirect incoming packets, it may help to activate it. The option for it may be located in your router/modem or firewall settings and may look something like this:

[img]http://puu.sh/2g0jy[/img]

These attackers require your IP address in order to attack you. They can easily get it through IRC, which publicly reveals your IP whenever you join a channel. The other method is via Steam, where they commonly collect your IP by Steam calling you. If you are able to successfully change your IP, do not accept Steam calls.

I would like to remind our would-be attackers that denial of service attacks are a federal offense. Given enough time and evidence, you will be pursued. The authorities will take action. Think twice before you act.

As I mentioned before, I am willing to help any member of the TF2 community as best I can.
Best of luck to you all.[/b]

Recently I and a bunch of other people in the TF2 community have been getting DDoSed while playing TF2 Pick Up Games or PUGs. Pugs are held on public IRC channels, servers, and mumble channels. All of this information is publicly available and your IP address is accessible.

A DoS attack is a denial of service attack. A DDoS attack is a Distributed Denial of Service attack. In either scenario the person sends a ton of information at you to disrupt your connection. A sophisticated attack cannot be stopped. If the person is an amateur or uses a unsophisticated service (likely purchased online through some company), you may be able to filter, redirect, or otherwise avoid the attack.

The easiest way to protect yourself is to never release your IP address.
However, because we all use public servers, this can be a problem.

There is nothing that can do to fully protect yourself from a denial of service attack. Even if you were personally able to to find a way to protect yourself with 100% certainty from the attacker, he can simply DDoS someone else and drop them from the Pug, effectively ruining it.

There is, however, something that you can do to protect yourself a little bit. The most important thing to do is to keep suspected DDoSers off of your Steam friends list. They can obtain your game info among other things, which will give them access to you. There is also a method of obtaining your IP that involves calling you via Steam. Do not accept any Steam calls. Skype is another way that they can easily access your IP address, which is why many people who stream other games have trouble with denial of service attacks. If possible, avoid using Skype. Lastly, if you use any IRC client, you can reveal your IP by joining channels. The one that I use that can help you to protect your IP address is mIRC. Using mIRC, you can mask your IP so that when you channels you will not automatically reveal your IP. The steps are listed below.

Step 1. Connect to Gamesurge/Qnet. Do not autojoin IRC channels. They reveal your IP.
Step 2. Change default IRC name to something random like asdfiounaewoisdfjaom
Step 3. After connecting and authorizing, you type in //mode $me +x which will mask your IP.
Step 4. Then type /nick misterslin or whatever your IGN is.
Step 5. Join the channels that you wanted to join.

Hopefully if enough people protect their IPs then we can make it a bit harder to get attacked.