Spam that is not Spam

[#1]

DAK.
I receive emails from an address something like asdfghjklqwertyu@oslobors.no,
the next email from the organisation will have the same suffix @oslobors.no but a different sender, I'd guess its machine generated.
As the sender is different every time and 'not known' the mail is redirected to my spam folder
How do I allow (withing plusnets spam system)  email from *@oslobors.no where * is a wildcard character.
many thanks

[#2]

If you read the notes above the box where you enter the whitelist you will see that you enter an email address OR a domain. So just put in oslobors.no

[#3]

Thanks jelv
obvious really - was looking under options in webmail