Is there any function to test for numeric ips?

Dear All,

I have a table with host names and some happen to be numeric IPs.

I would like to be able to filter out the later.

Is there any function pre-defined in the system that can test a particular text type value to see if it is a numeric ip?

Something that returns true if applied to '192.168.1.1' but false if applied to 'videos.sapo.pt' ?

I considered NOT LIKE '%.%.%.%' but I'm affraid it will filter out host names like 'www.google.com.br'

I've realized that, for ex, inet 'x.x.x.x' will fail if the input is not a numeric IP,
is there any simple and direct way to somewhat trap that error and convert it to a false value that can be used
in a WHERE clause?

This is not to be included in a program, I'm just interested in a query that I can do directly to the back end on a client program like pgAdmin.

I know very little ( nothing, actually...) about function creation in pgplsql, so, before investing in learning, I would like to know if there is any built in function that does the trick, so I can skip the (potential) learning curve.
So far, I've googled up and down but found none

Thanx in advance for your kind and valuable help

Best,
Oliveiros