What's the deal with 127.0.0.1? What does it mean?

[gamerex]

The most common IP I know about is 127.0.0.1 What is the deal with this IP?

 

[kimsland]

localhost (ie your computer)
http://en.wikipedia.org/wiki/Localhost

 

[DelJo63]

the Loopback address (127.0.0.1) is always internal to you machine:

1. you can NOT access other systems with this address and
2. other systems can not access this address on your machine.
3. but any process on your machine can use it

Normally our email readers access the Postoffice like

[emailClient]<--> pop3.domain.com (port 110) [postoffice]

but many email scanners are implemented:

[emailClient]<-->127.0.0.1(port 110) [emailScanner]<-->pop3.domain.com (port 110) [postoffice]