/etc/hosts Loopback entry Question

[Gordon_3]

Hi all,

Just wanna know what's the exact meaning for the entry in the /etc/hosts file of the loopback port. How does HP/UX 11 or above handle this loopback port? Does it require all process to explicitly specify the loopback for the connection; like Sybase, do I need to specify the loopback entry in the interface file? Will processes be able to just route all network packets through the TCP stack without going through the network card (i.e. "outside" and back)? Thx.

Gordon

[A. Clay Stephenson · Accepted solution]

Your loopback entry, e.g.
127.0.0.1 localhost loopback
sends traffic through a pseudo-device and is not associated with any hardware device.

[Gordon_3]

So, should those application file need to explicitly specify the loopback entry in those configuration file in order to use it? Thx.

[harry d brown jr]

localhost or loopback - both the same

live free or die
harry

[Sean OB_1]

Gordon,

The loopback is an internal address that uses the TCP stack, but no network card.

This is useful for things like an app talking to a database on the same machine.

For example I have a machine running apache and the sites use a MySql database on the same machine. So the web apps point to localhost as the server and talk to the database through that connection.

[Gordon_3]

Hi,

Thx for your info, yeah, u are right, the reason I ask this Q is because my Sybase collegues think that this entry can improve the server performance by using localhost instead of real hostname in the Sybase interface file. Just wanna know from yr experience, is that true for app. gain benefit on this entry. Also how to monitor if change this setting is successful or not? Finally where should I put this entry in the /etc/hosts. Any order? Put it into 1st line? Thx

Gordon