This is a test file with some bizzare lines

These get converted:

I'm going to ftp.howdy.com     yay!!
I'm going to abbaftp.howdy.com     yay!!
I'm going to ftpabba.howdy.com     yay!!
I'm going to abftpba.howdy.com     yay!!
I'm going to a_ftp_a.howdy.com     yay!!
I'm going to ***a_ftp_a.howdy.com***     yay!!

These are correctly not converted:

I'm going to 9bftpba.howdy.com     yay!!
I'm going to -bftpba.howdy.com     yay!!
I'm going to ***-bftpba.howdy.com***     yay!!

These test beginning and end of line conversions:

ftp.howdy.com     yay!!
I'm going to ftp.howdy.com
ftp.howdy.com

The same jazz but with www in the name:
 
These get converted:

I'm going to www.howdy.com     yay!!
I'm going to abbawww.howdy.com     yay!!
I'm going to wwwabba.howdy.com     yay!!
I'm going to abwwwba.howdy.com     yay!!
I'm going to a_www_a.howdy.com     yay!!
I'm going to ***a_www_a.howdy.com***     yay!!

These are correctly not converted:

I'm going to 9bwwwba.howdy.com     yay!!
I'm going to -bwwwba.howdy.com     yay!!
I'm going to ***-bwwwba.howdy.com***     yay!!

These test beginning and end of line conversions:

www.howdy.com     yay!!
I'm going to www.howdy.com
www.howdy.com