As I said before, you could just set sv_max_queries_sec to very small number, but that would lead to server not showing up in the server browser list. The same goes for the limiting - it will just drop out of the list and thats why there is a proxy which takes off the load from gameserver.
I can confirm what Ronny Schedel said that iptables does sometime redirect wrong packets to the proxy, I'm investigating this now... 2009/9/6 Guy Watkins <[email protected]> > Could you use the firewall to rate limit using "-m limit --limit 1/s > --limit-burst 10" or similar? > > Maybe something like this? > iptables -t nat -A PREROUTING -p udp -d SERVER_IP --dport SERVER_PORT -m > string --algo kmp --string 'TSource Engine Query' -m length --length 53 -m > limit --limit 1/s --limit-burst 10 -j REDIRECT --to-port 21015 > > Maybe won't even need the proxy if the firewall is limiting the DOS > packets? > > I have not tried the above. > > } -----Original Message----- > } From: [email protected] [mailto:hlds_linux- > } [email protected]] On Behalf Of Kaspars > } Sent: Sunday, September 06, 2009 9:43 AM > } To: Half-Life dedicated Linux server mailing list > } Subject: Re: [hlds_linux] A2S_INFO DDOS fix > } > } firewall rule could be adjusted to this: > } iptables -t nat -A PREROUTING -p udp -d SERVER_IP --dport SERVER_PORT -m > } string --algo kmp --string 'TSource Engine Query' -m length --length 53 > -j > } REDIRECT --to-port 21015 > } > } As for the rate limit... I don't think this is a good idea, because > } setting > } such a limit will make the server disappear from the browser list for > } legit > } clients. And if you have a good connection, you probably will not notice > } the > } traffic increase anyway. > } > } > } 2009/9/6 Ronny Schedel <[email protected]> > } > } > > } > I forgot an important part, your query proxy has still no rate limit. > It > } > can > } > be used to flood spoofed IP's. > } > > } > > } > > Hi, > } > > > } > > If you are on the hlds windows mailing list, then you probably > already > } > > know > } > > about A2S_INFO DDOS attacks. I have mistakenly posted a *fix* on the > } list > } > > for *nix servers which I should have posted here. > } > > > } > > In short: > } > > If your server gets ddosed with A2S_INFO packets, it will get really > } > > laggy. > } > > Setting sv_max_queries_sec to a low value will make the server > } disappear > } > > from the server browser list. I'm providing you with a UDP Caching > } Proxy > } > > which will query the server with A2S_INFO requests not more than once > } in > } > a > } > > five seconds and respond to the client with the cached data. > } > > > } > > Setup: > } > > 1. Get the source from http://www.gign.lv/tmp/querycache.c > } > > 2. Compile with gcc querycache.c -o querycache > } > > 3. Open an UDP port in firewall for the proxy server, lets say 21015 > } > > 4. Make sure you have iptables NAT, REDIRECT and string match support > } > > compiled into kernel or as modules > } > > 5. execute: iptables -t nat -A PREROUTING -p udp -d > } > > YOUR_EXTERNAL_TF2_SERVER_IP --dport YOUR_SERVER_PORT -m string --algo > } kmp > } > > --string 'TSource Engine Query' -j REDIRECT --to-port 21015 > } > > 6. Run querycache (probably under screen, so you can detach from it) > } > > > } > > I've been ddosed with about 300req/sec and it works good, however I > } don't > } > > give any warranty that it will work for you. > } > > _______________________________________________ > } > > To unsubscribe, edit your list preferences, or view the list > archives, > } > > please visit: > } > > http://list.valvesoftware.com/mailman/listinfo/hlds_linux > } > > > } > > } > > } > _______________________________________________ > } > To unsubscribe, edit your list preferences, or view the list archives, > } > please visit: > } > http://list.valvesoftware.com/mailman/listinfo/hlds_linux > } > > } _______________________________________________ > } To unsubscribe, edit your list preferences, or view the list archives, > } please visit: > } http://list.valvesoftware.com/mailman/listinfo/hlds_linux > > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list archives, > please visit: > http://list.valvesoftware.com/mailman/listinfo/hlds_linux > _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlds_linux
