"Henry R. Linneweh" <linneweh@concentric.net> wrote:

The reason above.net is not allowing Orbs to scan is because the owner of Orbs wants to scan every domain in the world for open relays

The logic of this escapes me. So ORBS scans for open relays. Their goals are no different from Above.net's scanning for vulnerable nameservers. The only fundamental differences are that Above.net is probing their own customers and using a different TCP/UDP port. If Above.net wants to filter scans that's one thing but they could have started better by filtering some of the many netscans we see from .kr and .cn subnets. I have no problem being scanned by either ORBS or Above.net. I do have a problem with upstream port filtering without my knowledge or express permission. One reason Above.net might block ORBS probably has not been discussed on NANOG. ORBS competes directly with RBL/DUL/RSS/mail-abuse.org. RBL and Above.net share management. Above.net's filters, it would seem, are the result of a business decision whose goal has less to do with customer safety than with inhibiting competition. With the exception of ORBS filtering both Above.net and ISC are doing a great job. Here's hoping Above.net takes the opportunity to improve by adopting more consistent policies on scanning and filtering. -- Roger Marquis Roble Systems Consulting http://www.roble.com/