Setting up outgoing mail on Ubuntu 10.10

Question

I am setting up a VPS on linode but I can't seem to setup a mail sending program like sendmail so that I can send emails through PHP.

I am stuck at the very first step of changing the hostname. I changed the entries under /etc/hostname and /etc/hosts but when I even reboot the VPS, then hostname -f shows hostname: Name or service not known

What's wrong? And any good tutorial for setting things up?

I am using nginx, if that somehow matters in any case.

Content of /etc/hosts

127.0.0.1 localhost
178.79.162.174 mail.bankpo.in

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

Content of /etc/hostname

mail.bankpo.in

And which hostname returns /bin/hostname

Answer 1

Edit /etc/hosts like this:

127.0.0.1       mail.bankpo.in      mail localhost
178.79.162.174       mail.bankpo.in      mail

add this to /etc/resolv.conf

domain bankpo.in
search bankpo.in

Then, reboot and try with /bin/hostname --fqdn

To set-up email, this is what I would do:

sudo apt-get dist-upgrade -y && sudo apt-get update -y
sudo reboot
sudo apt-get install postfix mailutils -y
sudo postconf -e "mydestination = mail.bankpo.in, bankpo.in, localhost.localdomain, localhost"
sudo postconf -e "mynetworks = 0.0.0.0/32"
sudo postconf -e "inet_interfaces = all"
sudo  /etc/init.d/postfix restart