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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