[cod] Some new cool iptables!
Boyd G. Gafford Ph.D.
drboyd at westportresearch.com
Fri Mar 9 13:40:12 EST 2012
How many servers are running on the one machine?
You might need to up the LIMITSTAT and LIMITINFO chains to more than
10/sec if you have a bunch of servers being handled by that rule.
10/sec is good for about 4 or 5 game servers.
You can see if your limits make sense by looking at "sudo iptables -L -v
-n" and looking at dropped packets in the LIMITSTAT and LIMITINFO
chains. If you see some of dropped packets (but are not under a
'getstatus' or 'getinfo' attack) then up it from 10 to maybe 20 or so.
Thanks,
/Boyd/
/__________________________________
Boyd G. Gafford Ph.D.
Manager of Software Development
Westport Research Associates Inc.
7001 Blue Ridge Blvd
Raytown, MO 64133
(816) 358-8990
drboyd at westportresearch.com
/
On 03/09/2012 12:09 PM, escapedturkey wrote:
> Seems to have killed qstat status check.
>
> Without ServerArk:
>
> qstat -old -R -P -a2s 208.43.15.2:27015 <http://208.43.15.2:27015>
> 208.43.15.2:27015 <http://208.43.15.2:27015> "EscapedTurkey.com
> Dallas, TX" map de_dust at (null) 0/32 players 1 ms
>
> ServerArk running:
>
> qstat -old -R -P -a2s 208.43.15.2:27015 <http://208.43.15.2:27015>
> 208.43.15.2:27015 <http://208.43.15.2:27015> no response
>
> This is what I am using:
>
> # The main logic of ServerArk, all done with /sbin/iptables!
>
> # Version 1.01
> # (C) 2012 Boyd G. Gafford Ph.D. (Usage is under the LGPL)
> # To contact me, simply post on the forum at elitewarriors.net
> <http://elitewarriors.net>.
> #
> # Please note these rules ONLY affect UDP packets to the game servers,
> nothing else!
> # This script will protect all Q3-protocol servers on the port 28960.
> It protects
>
> # against both 'getstatus' and 'getinfo' attacks, as well as
> 'getchallenge' atttacks,
> # even from a UDP flood with random source IPs.
>
> # Add a limit/drop chain for "getstatus" packets that limits it to 10
> a second for all servers.
> # If you are only protecting one server, you can set the number from
> 10 down to 4 (or 2 even).
>
> /sbin/iptables -N LIMITSTAT
> /sbin/iptables -A LIMITSTAT -p udp -m limit --limit 10/sec
> --limit-burst 10 -j ACCEPT
> /sbin/iptables -A LIMITSTAT -p udp -j DROP
>
>
> # Add a limit/drop chain for "getinfo" packets that limits it to 10 a
> second for all servers.
> # If you are only protecting one server, you can set the number from
> 10 down to 4 (or 2 even).
>
> /sbin/iptables -N LIMITINFO
> /sbin/iptables -A LIMITINFO -p udp -m limit --limit 10/sec
> --limit-burst 10 -j ACCEPT
> /sbin/iptables -A LIMITINFO -p udp -j DROP
>
>
> # Add a limit/drop chain for "getchallenge" packets that limits it to
> 5 a second for all servers.
> # If you are only protecting one server, you can set the number from 5
> down to 2. Setting it
> # at 2 means only 2 players could connect to the server per second.
> Set LIMITCONN to the
> # same, as there is one getchallenge/connect packet sequence per valid
> player connection.
>
> /sbin/iptables -N LIMITCHLG
> /sbin/iptables -A LIMITCHLG -p udp -m limit --limit 5/sec
> --limit-burst 5 -j ACCEPT
> /sbin/iptables -A LIMITCHLG -p udp -j DROP
>
>
> # Add a limit/drop chain for "connect" packets that limits it to 5 a
> second for all servers.
> # If you are only protecting one server, you can set the number from 5
> down to 2. Setting it
> # at 2 means only 2 players could connect to the server per second.
> Set LIMITCHLG to the
> # same, as there is one getchallenge/connect packet sequence per valid
> player connection.
>
> /sbin/iptables -N LIMITCONN
> /sbin/iptables -A LIMITCONN -p udp -m limit --limit 5/sec
> --limit-burst 5 -j ACCEPT
> /sbin/iptables -A LIMITCONN -p udp -j DROP
>
>
> # Add a limit chain that prevents more than 70 packets a second per
> player.
> # This is the main logic of ServerArk, but just performed by an
> iptable rule.
> # We allow up to 128 players which is enough for 4 servers full (at 32
> players each).
> # If you only have one server, you could the size and max to 32.
> # If you have players who have manually set their packet rate up to
> 100, just change the 70 to 100.
>
> /sbin/iptables -N LIMITPLRS
> /sbin/iptables -A LIMITPLRS -p udp -m hashlimit --hashlimit-name
> PLAYERS --hashlimit-above 100/sec --hashlimit-burst 100
> --hashlimit-mode srcip,srcport --hashlimit-htable-size 128
> --hashlimit-htable-max 128 --hashlimit-htable-gcinterval 1000
> --hashlimit-htable-expire 10000 -j DROP
> /sbin/iptables -A LIMITPLRS -p udp -j ACCEPT
>
>
> # Add the rules to pick out the various special packets and send them
> to appropriate limit chains.
> # To protect 5 ports, just specify a range like "--dport 28960:28964"
> below.
>
> /sbin/iptables -A INPUT -p udp --dport 27000:30000 -m string --string
> "getstatus" --algo bm --from 32 --to 33 -j LIMITSTAT
> /sbin/iptables -A INPUT -p udp --dport 27000:30000 -m string --string
> "getinfo" --algo bm --from 32 --to 33 -j LIMITINFO
> /sbin/iptables -A INPUT -p udp --dport 27000:30000 -m string --string
> "getchallenge" --algo bm --from 32 --to 33 -j LIMITCHLG
> /sbin/iptables -A INPUT -p udp --dport 27000:30000 -m string --string
> "connect" --algo bm --from 32 --to 33 -j LIMITCONN
>
>
> # Send all other packets (normal player packets) to the limit players
> chain.
> # A port range like "--dport 28960:28964" could also be used here as well.
> # /sbin/iptables -A INPUT -p udp --dport 28960 -j LIMITPLRS
>
> /sbin/iptables -A INPUT -p udp --dport 27000:30000 -j LIMITPLRS
>
> On Fri, Mar 9, 2012 at 11:41 AM, Boyd G. Gafford Ph.D.
> <drboyd at westportresearch.com <mailto:drboyd at westportresearch.com>> wrote:
>
> Yeah, if they flood "getstatus" and "getinfo", during the attack
> your server will not be visible from the master list.
>
> If they flood "getchallenge", during the attack nobody will be
> able to join your server.
>
> Once the attack ends, then you'll be visible again and people can
> join normally.
>
> Since most of these attacks are from spoofed random IP addresses
> (millions of them), you can't limit per IP, as no IP repeats.
>
> This set of rules is about the best I've found short of doing a
> whitelisted server, where you only allow IP's of known good
> players, and block everything else, and then people have to join
> the server with "connect IP:PORT". That's fairly inconvenient for
> most players, so these rules are about as good as you can get and
> still allow usage from the master list.
>
> Thanks,
>
> / Boyd/
>
> /__________________________________
> Boyd G. Gafford Ph.D.
> Manager of Software Development
> Westport Research Associates Inc.
> 7001 Blue Ridge Blvd
> Raytown, MO 64133
> (816) 358-8990 <tel:%28816%29%20358-8990>
> drboyd at westportresearch.com <mailto:drboyd at westportresearch.com>
> /
>
> On 03/09/2012 10:00 AM, Ruediger Meier wrote:
>> On Friday 09 March 2012, Boyd G. Gafford Ph.D. wrote:
>>> Just wanted to share these with the COD group here. I've been
>>> running these rules for about a week now, and they have been working
>>> wonderfully. Let me know if you end up using them and how they work
>>> for you.
>> Be aware that now it's easy for a attacker to make your servers
>> invisible for others by flooding your limit rules.
>> Maybe you should rather limit per ip.
>>
>> cu,
>> Rudi
>>
>>> #!/bin/bash
>>> # The main logic of ServerArk, all done with iptables!
>>> # Version 1.01
>>> # (C) 2012 Boyd G. Gafford Ph.D. (Usage is under the LGPL)
>>> # To contact me, simply post on the forum atelitewarriors.net <http://elitewarriors.net>.
>>> #
>>> # Please note these rules ONLY affect UDP packets to the game
>>> servers, nothing else!
>>> # This script will protect all Q3-protocol servers on the port 28960.
>>> It protects
>>> # against both 'getstatus' and 'getinfo' attacks, as well as
>>> 'getchallenge' atttacks,
>>> # even from a UDP flood with random source IPs.
>>>
>>> # Add a limit/drop chain for "getstatus" packets that limits it to 10
>>> a second for all servers.
>>> # If you are only protecting one server, you can set the number from
>>> 10 down to 4 (or 2 even).
>>> iptables -N LIMITSTAT
>>> iptables -A LIMITSTAT -p udp -m limit --limit 10/sec --limit-burst 10
>>> -j ACCEPT
>>> iptables -A LIMITSTAT -p udp -j DROP
>>>
>>> # Add a limit/drop chain for "getinfo" packets that limits it to 10 a
>>> second for all servers.
>>> # If you are only protecting one server, you can set the number from
>>> 10 down to 4 (or 2 even).
>>> iptables -N LIMITINFO
>>> iptables -A LIMITINFO -p udp -m limit --limit 10/sec --limit-burst 10
>>> -j ACCEPT
>>> iptables -A LIMITINFO -p udp -j DROP
>>>
>>> # Add a limit/drop chain for "getchallenge" packets that limits it to
>>> 5 a second for all servers.
>>> # If you are only protecting one server, you can set the number from
>>> 5 down to 2. Setting it
>>> # at 2 means only 2 players could connect to the server per second.
>>> Set LIMITCONN to the
>>> # same, as there is one getchallenge/connect packet sequence per
>>> valid player connection.
>>> iptables -N LIMITCHLG
>>> iptables -A LIMITCHLG -p udp -m limit --limit 5/sec --limit-burst 5
>>> -j ACCEPT
>>> iptables -A LIMITCHLG -p udp -j DROP
>>>
>>> # Add a limit/drop chain for "connect" packets that limits it to 5 a
>>> second for all servers.
>>> # If you are only protecting one server, you can set the number from
>>> 5 down to 2. Setting it
>>> # at 2 means only 2 players could connect to the server per second.
>>> Set LIMITCHLG to the
>>> # same, as there is one getchallenge/connect packet sequence per
>>> valid player connection.
>>> iptables -N LIMITCONN
>>> iptables -A LIMITCONN -p udp -m limit --limit 5/sec --limit-burst 5
>>> -j ACCEPT
>>> iptables -A LIMITCONN -p udp -j DROP
>>>
>>> # Add a limit chain that prevents more than 70 packets a second per
>>> player. # This is the main logic of ServerArk, but just performed by
>>> an iptable rule.
>>> # We allow up to 128 players which is enough for 4 servers full (at
>>> 32 players each).
>>> # If you only have one server, you could the size and max to 32.
>>> # If you have players who have manually set their packet rate up to
>>> 100, just change the 70 to 100.
>>> iptables -N LIMITPLRS
>>> iptables -A LIMITPLRS -p udp -m hashlimit --hashlimit-name PLAYERS
>>> --hashlimit-above 70/sec --hashlimit-burst 70 --hashlimit-mode
>>> srcip,srcport --hashlimit-htable-size 128 --hashlimit-htable-max 128
>>> --hashlimit-htable-gcinterval 1000 --hashlimit-htable-expire 10000 -j
>>> DROP iptables -A LIMITPLRS -p udp -j ACCEPT
>>>
>>> # Add the rules to pick out the various special packets and send them
>>> to appropriate limit chains.
>>> # To protect 5 ports, just specify a range like "--dport 28960:28964"
>>> below. iptables -A INPUT -p udp --dport 28960-m string --string
>>> "getstatus" --algo bm --from 32 --to 33 -j LIMITSTAT
>>> iptables -A INPUT -p udp --dport 28960-m string --string "getinfo"
>>> --algo bm --from 32 --to 33 -j LIMITINFO
>>> iptables -A INPUT -p udp --dport 28960-m string --string
>>> "getchallenge" --algo bm --from 32 --to 33 -j LIMITCHLG
>>> iptables -A INPUT -p udp --dport 28960-m string --string "connect"
>>> --algo bm --from 32 --to 33 -j LIMITCONN
>>>
>>> # Send all other packets (normal player packets) to the limit players
>>> chain. # A port range like "--dport 28960:28964" could also be used
>>> here as well. iptables -A INPUT -p udp --dport 28960-j LIMITPLRS
>>> /
>>> /Also, you can do an "iptables -L -v -n" to see what kind of attacks
>>> these rules have blocked. Here's an example of this command after a
>>> "getchallenge" flood attack from random IPs, on our Dallas server
>>> running on port 29070.
>>>
>>> ew at server1:~$ sudo iptables -L -v -n
>>> Chain INPUT (policy ACCEPT 11368 packets, 1538K bytes)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 3880 177K LIMITSTAT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> udp dpt:29070 STRING match "getstatus" ALGO name
>>> bm FROM 32 TO 33
>>> 14036 617K LIMITINFO udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> udp dpt:29070 STRING match "getinfo" ALGO name bm
>>> FROM 32 TO 33
>>> 37M 1620M LIMITCHLG udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> udp dpt:29070 STRING match "getchallenge" ALGO
>>> name bm FROM 32 TO 33
>>> 17 4989 LIMITCONN udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> udp dpt:29070 STRING match "connect" ALGO name bm
>>> FROM 32 TO 33
>>> 237K 17M LIMITPLRS udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> udp dpt:29070
>>>
>>> Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
>>> pkts bytes target prot opt in out source
>>> destination
>>>
>>> Chain OUTPUT (policy ACCEPT 343K packets, 54M bytes)
>>> pkts bytes target prot opt in out source
>>> destination
>>>
>>> Chain LIMITCHLG (1 references)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 40025 1761K ACCEPT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> limit: avg 5/sec burst 5
>>> *37M 1618M DROP* udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0>
>>>
>>> Chain LIMITCONN (1 references)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 17 4989 ACCEPT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> limit: avg 5/sec burst 5
>>> 0 0 DROP udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0>
>>>
>>> Chain LIMITINFO (1 references)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 14036 617K ACCEPT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> limit: avg 10/sec burst 10
>>> 0 0 DROP udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0>
>>>
>>> Chain LIMITPLRS (1 references)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 1642 104K DROP udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> limit: above 70/sec burst 70 mode srcip-srcport
>>> htable-size 128 htable-max 128
>>> 236K 17M ACCEPT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0>
>>>
>>> Chain LIMITSTAT (1 references)
>>> pkts bytes target prot opt in out source
>>> destination
>>> 3868 177K ACCEPT udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0> limit: avg 10/sec burst 10
>>> 12 516 DROP udp -- * *0.0.0.0/0 <http://0.0.0.0/0>
>>> 0.0.0.0/0 <http://0.0.0.0/0>
>>>
>>> Notice the bolded packet/byte statistics for the "getchallenge" drop
>>> chain named LIMITCHLG. A total of 37 million packets dropped. I was
>>> on the game during this attack, and although the server did lag a bit
>>> from the sheer size of the flood (almost saturating the bandwidth),
>>> nobody lagged out. Without this rule, the game server deadlocked.
>>>
>>> Also notice you can tell how many players have connected to the
>>> server, as the LIMITCONN status shows 17 packets accepted. So during
>>> this time we had 17 players join the game.
>>>
>>> You can also see how many people requested the servers in game (as
>>> well as other services like GameTracker getting info on you), as that
>>> corresponds to the LIMITSTAT and LIMITINFO chains.
>>>
>>> Another cool thing you can do is "cat /proc/srv/ipt_hashlimit/PLAYERS
>>> to see the IP addresses of all the players currently connected to the
>>> server(s). Once a player quits playing, he goes out of this file
>>> automatically after 10 seconds.
>>>
>>> I may refine these a bit further, but for now, these seem to be
>>> working well on our VPS.
>>>
>>> Thanks,
>>>
>>> /Boyd/
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>> http://icculus.org/mailman/listinfo/cod
>>
>
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> http://icculus.org/mailman/listinfo/cod
>
>
>
>
> --
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>
>
>
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