Problema configuración Postfix en Ubuntu 12.10

Estoy trabajando en una web y una de las funcionalidades es el envio de emails para confirmacion de registro o recuperacion de passwords. El desarrollo de la web lo estoy haciendo en local y bajo Ubuntu 12.10. Para cubrir esta necesidad instale Postfix y configure el archivo de main. Cf de forma muy simple como sigue:

# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
Append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
Myhostname = localhost
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = localhost
relayhost =
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
myorigin = /etc/mailname
home_mailbox = Maildir/
mynetworks = 127.0.0.0/8 192.168.1.0/24 [::1]/128 [fe80::]/64
default_transport = smtp
relay_transport = smtp

Despues abri el puerto 25:

Iptables -A INPUT -p tcp -s 0/0 --sport 25 -d 202.54.1.20 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -s 202.54.1.20 --sport 1024:65535 -d 0/0 --dport 25 -m state --state NEW, ESTABLISHED -j ACCEPT

Y comprobe que realmente lo estaba:

nmap --top-ports 10 localhost
Starting Nmap 6.00 ( http://nmap.org/ ) at 2013-03-25 15:57 WET
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000030s latency).
PORT STATE SERVICE
21/tcp closed ftp
22/tcp closed ssh
23/tcp closed telnet
25/tcp open smtp
80/tcp open http
110/tcp closed pop3
139/tcp closed netbios-ssn
443/tcp closed https
445/tcp closed microsoft-ds
3389/tcp closed ms-wbt-server

Pero cuando intento realizar un test:

echo testing | mail -s Bla ***************@gmail.com

obtengo el siguiente error:

Mar 25 15:58:24 maadia postfix/qmgr[20525]: 51B53C0E4F: from=<root@maadia>, size=313, nrcpt=1 (queue active)
Mar 25 15:58:24 maadia postfix/qmgr[20525]: 81ACFC0E31: from=<root@maadia>, size=325, nrcpt=1 (queue active)
Mar 25 15:58:24 maadia postfix/qmgr[20525]: 4EB18C0E4E: from=<root@maadia>, size=315, nrcpt=1 (queue active)
Mar
 25 15:58:24 maadia postfix/error[21210]: 51B53C0E4F: 
to=<***************@@gmail.com>, relay=none, delay=1136, 
delays=1136/0.01/0/0.12, dsn=4.4.1, status=deferred (delivery 
temporarily suspended: connect to 
alt2.gmail-smtp-in.l.google.com[173.194.69.27]:25: Connection timed out)
Mar
 25 15:58:24 maadia postfix/error[21211]: 81ACFC0E31: 
to=<***************@@gmail.com>, relay=none, delay=4887, 
delays=4887/0.01/0/0.14, dsn=4.4.1, status=deferred (delivery 
temporarily suspended: connect to 
alt2.gmail-smtp-in.l.google.com[173.194.69.27]:25: Connection timed out)
Mar
 25 15:58:24 maadia postfix/error[21213]: 4EB18C0E4E: 
to=<***************@@gmail.com>, relay=none, delay=2876, 
delays=2876/0.02/0/0.13, dsn=4.4.1, status=deferred (delivery 
temporarily suspended: connect to 
alt2.gmail-smtp-in.l.google.com[173.194.69.27]:25: Connection timed out)
Mar 25 15:58:37 maadia postfix/pickup[20524]: 9D9EDC0EEB: uid=0 from=<root@maadia>
Mar 25 15:58:37 maadia postfix/cleanup[21220]: 9D9EDC0EEB: message-id=<20130325155837.9D9EDC0EEB@localhost>
Mar 25 15:58:37 maadia postfix/qmgr[20525]: 9D9EDC0EEB: from=<root@maadia>, size=315, nrcpt=1 (queue active)
Mar
 25 15:58:37 maadia postfix/error[21210]: 9D9EDC0EEB: 
to=<***************@@gmail.com>, relay=none, delay=0.24, 
delays=0.17/0/0/0.07, dsn=4.4.1, status=deferred (delivery temporarily 
suspended: connect to alt2.gmail-smtp-in.l.google.com[173.194.69.27]:25:
Connection timed out)

La verdad es que no se si sera algún problema con el fichero main. Cf u otra cosa, el caso es que necesito poder probar la funcionalidad del envío
de emails y me esta siendo imposible debido a este problema. Si puedes
echarme una mano o proponerme alguna alternativa para poder probar esta
funcionalidad estaría genial.