Port is open but I am unable to connect
Jacob Friis Larsen
jfl at list.idg.dk
Wed Sep 8 08:47:18 CEST 2004
> All your rules (apart from lo interface) are for INPUT chain. No rules
> for OUTPUT chain (so all return packets get dropped there). You are
> missing "-A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT" at
> the begining of your rules (just after similar INPUT line you already
> have).
Sounds logic. I changed it in the script below, and will try it out
later when I can get to the server.
> BTW, what's the point of accepting connections to port 20? It's FTP
> port used for active data transfers, and connections are made *from*
> it, not *to* it. Since you have (will have) "just accept anything
> related I don't care" rules, just add "modprobe ip_nat_ftp" line
> somewhere into your script, and FTP will work (you don't need that
> port 20 line).
OK, I changed that too.
Thanks a lot!
Jacob
>> This is my script:
>
> [snip]
>
modprobe ip_nat_ftp
>> # STATE RELATED for router
>> iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
>>
>> # Localhost
>> iptables -A INPUT -i lo -j ACCEPT
>> iptables -A OUTPUT -o lo -j ACCEPT
>>
>> # Open ports on router for server/services
#iptables -A INPUT -s 1.2.3.4 -j ACCEPT -p tcp --dport 20 -m state
>> --state NEW
>> iptables -A INPUT -s 1.2.3.4 -j ACCEPT -p tcp --dport 21 -m state
>> --state NEW
>> iptables -A INPUT -s 1.2.3.4 -j ACCEPT -p tcp --dport 22 -m state
>> --state NEW
>> iptables -A INPUT -j ACCEPT -p tcp --dport 25 -m state --state NEW
>> iptables -A INPUT -j ACCEPT -p tcp --dport 80 -m state --state NEW
>> iptables -A INPUT -j ACCEPT -p tcp --dport 143 -m state --state NEW
>> iptables -A INPUT -j ACCEPT -p tcp --dport 993 -m state --state NEW
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