I answer to mysqelf.
Form some mysterious reason that relationship is now in dom_param.
dom_id points to hosting.dom_id
look for a param = 'ip_addr_id'
Its value points to IP_Addresses.
So, for example...
SELECT domains.name, IP_Addresses.ip_address
FROM domains
INNER JOIN hosting ON domains.id = hosting.dom_id
INNER JOIN dom_param ON hosting.dom_id = dom_param.dom_id AND dom_param.param = 'ip_addr_id'
INNER JOIN IP_Addresses ON dom_param.val = IP_Addresses.id
A pain in the *** to obtain consistently the IP through versions... tough...