Iptables and Ipset blacklist, blocking email and webmail access

[Alekis]

Hi all,

I have one web server (Linux Ubuntu, Apache, MySql, Plesk), with some sites, and after two invasions, and hundred of invasion attempts, I'm trying to get more ensurance, with iptables and ipset blacklist, following one tutorial that I found in the web.
Occour that, after to apply the iptables rule below, the server stopped of sending email, via Thunderbird and also via webmail (roundcube).

The rule is:

iptables -I INPUT -m set --match-set blacklist src -j DROP

After that, I tried to correct any possible error using:

iptables -A INPUT -p tcp --dport 25 -j ACCEPT
iptables -A INPUT -p tcp --dport 110 -j ACCEPT
iptables -A INPUT -p tcp --dport 143 -j ACCEPT
iptables -A INPUT -p tcp --dport 587 -j ACCEPT
iptables -A INPUT -p tcp --dport 943 -j ACCEPT

Until...

iptables -A INPUT -p tcp --dport 80 -j ACCEPT

(This last, I did as despair, because I'm sure that I don't know, what kind of consequences, can I have.)

The problem is, that I introduced the rules after the first command, what I'm not sure is correct.

Also, I would like to ask to the experts the kindness of answer...
1 - Don't the first rule typed to block just the IPs from the blacklist? So why it blocked the emails for me?
2 - What can I do, to unblock the e-mail?

Thank you in advanced,

Alekis