People who deal daily with several e-mail accounts often adopt an e-mail client such as Mozilla Thunderbird instead of a web based service in order to download at once all their e-mails, organize them and work off-line.
If you work in a firewalled environment (your university, your company, etc…) that allows you to use your e-mail client in order to download your emails through POP3 but not to send messages using the standard SMTP on port 25 (the standard port used by SMTP services), you can try the following workaround…
In most cases many institutions block port 25 in order to avoid possible spamming from their network, however these networks usually allow to use port 465 to send e-mails via SMTP from any client through a secure (SSL) connection.
If you have a Gmail account you can simply configure Gmail SMTP in your e-mail client using the following parameters:
Port: 465 (SSL)
password: your gmail password
If you send emails from different addresses through your e-mail client, they will be overwritten by default with your Gmail address which will appear in the “from” field, however you can avoid this by adding your email address as “another address you own” in Gmail. To do this just go to Gmail website, login and go to Settings -> Accounts -> Add another email address you own.
You will be able to send email from firstname.lastname@example.org throught your favourite email client and a secure connection to Gmail SMTP on port 465, possibily bypassing firewall blocks on standard port 25.