I don't know - but I do find this in their email headers:
At the bottom of that page you can even find the Swisscom logo.
My 2 cents, hope they help!
On 10/31/17 15:08, Benoit Panizzon wrote:
A Mailserver from a business customer of ours is blacklisted @ bluewin.
The Error Message from Bluewin MXes directing to the removal site:
Our customer has requested removal via this form, no success.
Our customer has contacted bluewin and opened a trouble ticket. He got
the information that his ISP (us) should take care to remove his IP
from the blacklists, but is not getting any information about which
We are at a loss. Does anyone know what kind of blacklists bluewin uses?