iptables and INVALID packet filtering.

Hi

I would only ask about iptables (1.4.14-3.1) rule, which is responsible for
filtering INVALID packets. If I decide to use this rule;

>> iptables -A INPUT -m conntrack --ctstate INVALID -j DROP

That's an example. By using this rule, iptables will also check tcp and udp
protocols or should I use something like;

>> iptables -A INPUT -p tcp (...)
>> iptables -A INPUT -p udp (...)

Which solution/rule is correct and it is better to implement?

Best regards.