Iptables ACCEPT and DROP

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Dear Friends:

I have observe a behavior of iptables which I need to understand.

216.155.193.168 is the IP address of Yahoo's messenger site and it
listens on port 5050.

The following command will allows the machine to connect to
216.155.193.168.

iptables -A OUTPUT -o eth0 -p tcp -d 216.155.193.168 --dport 5050 -j
ACCEPT

After that, I see output like following:

#telnet 216.155.193.168 5050
Trying 216.155.193.168...
Connected to 216.155.193.168.
Escape character is '^]'.

Now when I issue
iptables -A OUTPUT -o eth0 -p tcp -d 216.155.193.168 --dport 5050 -j
DROP
And
iptables -A OUTPUT -o eth0 -p tcp -d 216.155.193.168 --dport 5050 -j
REJECT

Still, it allows connection to 216.155.193.168 on port 5050.

How does this work? It seems -j DROP is not opposite of -j ACCEPT. How
can stop this?

Kind regards.

Ravi Verma



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