J’ai trouvé la declaration suivante:
Outbound Email policy of UPC GmbH for this IP range
It is the policy of UPC GmbH that unauthenticated email sent from this IP address should be sent out only via the designated outbound mail server allocated to UPC GmbH customers. To find the hostname of the correct mail server to use, customers should consult the original signup documentation or contact UPC GmbH Technical Support.
y’a t’il des relay smtp fournis par UPC quelque part pour les clients ?