Hi there, I would like to share some thoughts on reverse DNS with you. In my experience, reverse DNS often works well with larger organisations that have been assigned a /24 IPv4 range or greater. On the other hand, it almost never works with smaller organisations using smaller ranges, e.g. on ADSL lines. As I see it, there is a general trend that more and more small and mid-size businesses uses ADSL lines for connectivity. Since IPv4 addresses are scarce, these businesses are often assigned IPv4 ranges smaller than /24 - many only get a /30 range. Nevertheless, they still operates servers for various purposes. The problem is that ISPs typically are very hesitant to administer reverse DNS for these addresses. Either these addresses have no reverse DNS at all, or they resolve to a semi-random host name (e.g. address aaa.bbb.ccc.ddd resolves to aaa.bbb.ccc.ddd.adsl.isp-name.com). If the ISP (or whoever administers reverse DNS for the /24 range) do not wish to help out, there is really nothing the end user can do. Apart from being _really_ annoying to the end user, it also undermines reverse DNS as such: It is already difficult to convince everybody to set up reverse DNS, but even if an end user wants to do it, it may not be possible for him. I am aware that it would take some work for RIPE NCC to force every ISP to properly administer reverse DNS, but there are several costless methods that would help a lot. Please consider these suggestions: a) Make it mandatory for ISPs to offer classless reverse delegation to end users with RIPE-assigned IP ranges (i.e. for PA IP ranges that has a inetnum object with an end user as admin-c). Even if this would not be actively enforced, it would be a great help to end users if they could point to an official RIPE policy on this. Even a web page saying that LIRs _should_ do so would be a help. b) Make it mandatory for ISPs to offer either classless delegation or reverse DNS at IP-level for all its assigned addresses. Again, if there are no ressources to enforce it, it would still help to make it official RIPE NCC policy. c) Extend the new reverse delegation system to include classless delegation of PA addresses. For this to work, it would probably be necessary to move master DNS for all split ranges to RIPE NCC, which of course would increase the load on RIPE NCC. Administration, on the other hand, could be fully automatised. There are probably many other ways, too. Anyhow, I would really like a solution to this. Sincerely, Jørgen E. Larsen CTO Elgaard Data jel(at)elgaard.net