Do you have problems sending mail to a user at the Astronomical Observatory (i.e. to user@astro.ku.dk) ? Did you receive a message telling you that your mail server or domain has been black-listed due to spam problems (or something similar) ? Did the message contain the IP address of the black-listed server (it should) ? Then just read on !
If you know the IP address of the black-listed server, you can easily request that this address is inserted into a special white-list database maintained at the Astronomical Observatory (AO). This is simply done by typing in the IP address into the field below. An IP address consists of 4 numbers (each within the range 1-255) separated by dots (.) as in this example: 130.225.113.232 . Your browser must have JavaScript enabled in order to use this facility.
Note: If your home PC is connected to the internet through an ISP, then you MUST send mail through your ISP's mail server (SMTP server), sending mail directly from your PC to AO is not supported. This is especially true if your ISP gives you a dynamic IP address, i.e. you get a new IP each time you connect to the internet. Dynamic IP addresses are normally used with modem dial-up lines, but some times also used with ADSL lines (this depends on you ISP). In other words: you should only white-list your ISP's mail server IP address, not the IP address of your own PC. If you white-list a private PC connected to an ISP (via modem or ADSL), then this white-listing may be removed again.
It may take up to five minutes before the white-listing takes effect, so you must wait at least five min. before you send your e-mail again. If you don't send an e-mail to our domain within a few days - from the white-listed host, then the white-listing may be removed again.
If you want to know more about how the spam filter works at the Astronomical Observatory, then follow this link.