A tool to test if a port is blocked by firewall

To test if an  Internet socket port on an external server is open or blocked by a firewall, input the ip address and port in this address
http://www.alicka.com/tools.html
you'll get if the port is blocked or open via firewall.

Although the port is open in firewall,  if it is not actively used, it will still show closed.

To test gmail ssl port 465, download openssl Win32 OpenSSL v1.0.1f Light from:
http://slproweb.com/products/Win32OpenSSL.html
Run the program and assume you installed it in C:\OpenSSL-Win32:
run
C:\OpenSSL-Win32\bin\openssl  s_client -connect smtp.gmail.com:465
to see if port 465 open.

To if test gmail port 25 open in firewall: in command prompt run
nslookup -q=MX gmail.com
You can get
Server:  ns-int-1.netcom.ubc.ca
Address:  137.82.1.2

Non-authoritative answer:
gmail.com       MX preference = 40, mail exchanger = alt4.gmail-smtp-in.l.google
.com
gmail.com       MX preference = 5, mail exchanger = gmail-smtp-in.l.google.com
gmail.com       MX preference = 10, mail exchanger = alt1.gmail-smtp-in.l.google
.com
gmail.com       MX preference = 20, mail exchanger = alt2.gmail-smtp-in.l.google
.com
gmail.com       MX preference = 30, mail exchanger = alt3.gmail-smtp-in.l.google
.com

gmail.com       nameserver = ns1.google.com
gmail.com       nameserver = ns3.google.com
gmail.com       nameserver = ns4.google.com
gmail.com       nameserver = ns2.google.com
gmail-smtp-in.l.google.com      internet address = 74.125.129.26
gmail-smtp-in.l.google.com      AAAA IPv6 address = 2607:f8b0:4002:c01::1a
alt1.gmail-smtp-in.l.google.com internet address = 74.125.193.26
alt1.gmail-smtp-in.l.google.com AAAA IPv6 address = 2607:f8b0:4002:c01::1a
alt2.gmail-smtp-in.l.google.com internet address = 74.125.196.27
alt2.gmail-smtp-in.l.google.com AAAA IPv6 address = 2607:f8b0:4002:c01::1b
alt3.gmail-smtp-in.l.google.com internet address = 173.194.68.26
alt3.gmail-smtp-in.l.google.com AAAA IPv6 address = 2607:f8b0:4002:c01::1b
alt4.gmail-smtp-in.l.google.com internet address = 173.194.75.27
alt4.gmail-smtp-in.l.google.com AAAA IPv6 address = 2607:f8b0:4002:c01::1a
ns1.google.com  internet address = 216.239.32.10
ns2.google.com  internet address = 216.239.34.10
ns3.google.com  internet address = 216.239.36.10
ns4.google.com  internet address = 216.239.38.10
Pick up one mail exchanger for example alt3.gmail-smtp-in.l.google.com, run
telnet alt3.gmail-smtp-in.l.google.com 25
if successful, you can get
221 2.0.0 closing connection w8si3911414qag.86 - gsmtp
type quit to quit telnet.
Do not too trust your host provider. Test it. Some important ports: port 25 SMTP (Simple Mail Transfer Protocol) and 465 Secure SMTP (often used by email providers such as Google-Apps for outbound email traffic), ftp (port 21), sftp (port 22), Web service (ports 80, 8080), MySQL (port 3306), Flash Media server (port 1935).

In PHPMailer, if we use ssl in smtp.gmail.com, port 465 outbound in Firewall should be open.
If we use other regular   outside smtp mail server, port 25 outbound should be open.

Inbound rules allow other system to connect to yours, ex if you would like someone to connect to your windows shares, ftp, web server etc.
Outbound rules allow applications on you system to connect to other systems, ex if you want to connect to a web site, IM or some elses ftp.
Both the inbound and outbound rules will have no effect if your firewall is off.