'unix' Archive | RSS

What’s My IP Address? 

That’s an interesting question!
First the High Level Overview For Beginners
OK, maybe first we should ask ‘Why do we care?’
IP stands for Internet Protocol. It’s part of the TCP/IP (Transmission Control Protocol / Internet Protocol) network protocol which is used, pretty much, by all computers connected to a network. By network I mean a [...]

Talking to Sendmail 

Talking directly to sendmail.
You can use telnet to talk directly to sendmail. This allows you to create mail from a different account. Sendmail uses port 25 by default.
$ telnet your.mailserver.address.com 25
You should get an introductory message from sendmail.
> helo your.domain.com
Sendmail responds with address details and ‘pleased to meet you’
> mail from: person@address.mail.is.from.com
Sendmail should echo back [...]