[SOLVED] Iptables breaks mediastreaming from server
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I have a small server, from which I stream video files, from a samba share.
I have enabled iptables, and setup basic rules, but for some reason, when these rules are active, the streaming stops suddently. Sometimes already after 3 minutes, sometimes after 20 minutes, so there is no clear pattern.
I have tried to debug with tcpdump, but there is nothing to se here.
Any ideas to, what is causing this?
The iptables rule looks like this.
Chain INPUT (policy DROP 67 packets, 8666 bytes)
num pkts bytes target prot opt in out source destination
1 6 360 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22 state NEW
2 22 2088 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:137 state NEW
3 1 236 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:138 state NEW
4 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:139 state NEW
5 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:445 state NEW
6 141 9533 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
The best way to "debug" firewall rule sets is to use "-j LOG" rules before "-j DROP" decisions to see what actually gets dropped. Additionally attaching output of 'iptables-save' provides a more accurate view of what rules are actually in use.
That is an interesting twist, seeing as UDP does not have 'states' like TCP. This link suggests that IPTables may be remembering the IP:Port used as part of the connection tracking. It alludes to analysis of packets and replies, but there is nothing in UDP that says a reply is imminent.