Iptables seems to be blocking postfix

Iptables seems to be blocking postfix

I'm using gmail as a relay to send mail through postfix. I can send mail
when the firewall is down, but I can't when its up. What should I add to
these iptables rules to send mail?
*filter
:INPUT DROP [14:1434]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
#SSH
##HOME
-A INPUT -i eth0 -p tcp -s 1xx.1xx.1.xx/255.255.255.0 --dport 9991 -m
state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p tcp --sport 9001 -m state --state ESTABLISHED -j
ACCEPT
##PSd
-A INPUT -i eth0 -p tcp -s xx.xxx.xxx.xxx/255.255.255.0 --dport 9991 -m
state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -o eth0 -p tcp --sport 9991 -m state --state ESTABLISHED -j
ACCEPT
#HTTP
-A INPUT -i eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A OUTPUT -o eth0 -p tcp --sport 80 -m state --state ESTABLISHED,RELATED
-j ACCEPT
#HTTPS
-A INPUT -i eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A OUTPUT -o eth0 -p tcp --sport 443 -m state --state
ESTABLISHED,RELATED -j ACCEPT
#Loop Back (FOR MY SQL!!)
-A INPUT -i lo -j ACCEPT
-A OUTPUT -o lo -j ACCEPT
#Stopping DDOS
-A INPUT -p tcp --dport 80 -m limit --limit 25/minute --limit-burst 100
-j ACCEPT
-A INPUT -p tcp --dport 443 -m limit --limit 25/minute --limit-burst 100
-j ACCEPT
#Allowing Mail
-A OUTPUT -o eth0 -p tcp --sport 25 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A OUTPUT -o eth0 -p tcp --dport 25 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A INPUT -i eth0 -p tcp --sport 25 -m state --state ESTABLISHED -j ACCEPT
# DNS
-A INPUT -p tcp -m tcp --sport 53 -j ACCEPT
-A INPUT -p udp -m udp --sport 53 -j ACCEPT
#apt-get
-A INPUT -p tcp --sport 80 -j ACCEPT
COMMIT
Here's something I tried
-I OUTPUT -p tcp --dport 465 -j ACCEPT
-I OUTPUT -p tcp --dport 587 -j ACCEPT
And obviously, this rule does nothing right now
#Allowing Mail
-A OUTPUT -o eth0 -p tcp --sport 25 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A OUTPUT -o eth0 -p tcp --dport 25 -m state --state NEW,ESTABLISHED -j
ACCEPT
-A INPUT -i eth0 -p tcp --sport 25 -m state --state ESTABLISHED -j ACCEPT
I've searched a lot, and variations of the aforementioned rules are all
that I found. I apologize if this is a beginner problem.
If there's more information needed to answer this question let me know!!