...

Step 1:

Bluewin does a reverse DNS lookup on your IP (195.141.232.78), which returns the following:

# nslookup

...

195.141.232.78

;; Truncated, retrying in TCP mode. Server: www.multipop.ch. Address: 195.141.232.253#53

78.232.141.195.in-addr.arpa name = mailhost.aa795.ch. 78.232.141.195.in-addr.arpa name = mailhost.aerni.net.

plus another 20 hosts

This is a silly reverse setup. A reverse lookup should only return

one hostname, not 20.

/Per Jessen, Herrliberg

Yes, I agree. This is really a bad design and has nothing to do with DNS problems on the bluewin side, even if the bluewin DNS might have troubles resolving truncated requests, IMHO.

Cheers, Florian