If you have the ftp mirror and you have any older version of linux just open the terminal and use the "dig" command with the main directory of the mirror , it will obtain the IP address for you.
e.g :
this is a mirror:
ftp:// bla.bla.bla/ blu blu blu/ ble ble ble
write :
dig bla.bla.bla
and see the result
regards
