1 Topic by FFanta

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Topic: Servers can't find master servers

Hi, for some reason my teeworlds servers can't connect to the master servers. Players are able to join and play though.

When my firewall is turned off everything works fine, but with these rules it doesn't.

iptables -A INPUT -p udp -s 0/0 -d $SERVER_IP --sport 513:65535 --dport 8303 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p udp -s $SERVER_IP -d 0/0 --sport 8303 --dport 513:65535 -m state --state NEW,ESTABLISHED -j ACCEPT

For other applications like TeamSpeak 3 these rules work perfectly fine. Did I forget anything or is there another reason for this problem?

2 Reply by Dune

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Re: Servers can't find master servers

I don't know about the specific rules, but make sure that your server is indeed running on 8303 port. Allow UDP/TCP.

Not Luck, Just Magic.

3 Reply by BeaR

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Re: Servers can't find master servers

the server communicates over port 8300 with the master servers

4 Reply by m!nus

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Re: Servers can't find master servers

Really depends on how the rest of your firewall is set up. If you have connection tracking enabled a simple
iptables -A INPUT -p udp --dport 8303 -j ACCEPT
should suffice.

5 Reply by FFanta (edited by FFanta 2014-01-18 14:15:12)

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Re: Servers can't find master servers

Found the solution.. I completely forgot about port 53.

iptables -A OUTPUT -p udp -s $SERVER_IP -d 0/0 --dport 53 -j ACCEPT
iptables -A INPUT -p udp -s 0/0 -d $SERVER_IP --sport 53 -j ACCEPT

6 Reply by m!nus

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Re: Servers can't find master servers

Ouch. You can leave out the -d and -s if you use 0/0. Otherwise I suggest you limit the IPs to those of your DNS server (somewhat helpful when you get DNS amplification attacks)