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  Reply # 845166 25-Jun-2013 18:22
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Reverse DNS is interesting. For inet (ipv4), we just create one rDNS record per IP address and this works a treat.
However, with inet6, each customer currently receives a /48 from us (via DHCPv6 from our BNG). So, we need to return an rDNS response not just for a single address, but a whole /48 prefix of addresses for each customer.

If we were to enter an rDNS for each address, we would need to enter 1 208 925 819 614 629 174 706 176 (1.2 septillion) records for each customer. This may present a scaling issue.

In all seriousness though, there will be methods to solve this (likely by returning a particular PTR record for anything inside a particular prefix); we're going to investigate this, but because it's just a nice thing to have, it's a low priority at this stage.

Cheers
TW




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  Reply # 845168 25-Jun-2013 18:26
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quakeguy: Reverse DNS is interesting. For inet (ipv4), we just create one rDNS record per IP address and this works a treat.
However, with inet6, each customer currently receives a /48 from us (via DHCPv6 from our BNG). So, we need to return an rDNS response not just for a single address, but a whole /48 prefix of addresses for each customer.

Cheers
TW


yeah, but for instance with snap hardly any of the routers have reverse dns entries.  but it's not just snap..

like doing a traceroute to www.kame.net i see two dns entries, one for telstraclear, and one for wide.ad.jp.


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  Reply # 845170 25-Jun-2013 18:29
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quakeguy:
In all seriousness though, there will be methods to solve this (likely by returning a particular PTR record for anything inside a particular prefix); we're going to investigate this, but because it's just a nice thing to have, it's a low priority at this stage.


I wonder what the general way that this is meant to be resolved is.  To me it seems like it'd be most sensible to have DNS delegation go to the customer who can then choose to expose connected hosts or not but I don't know if there's CPE type systems that easily work like that.

With dnsmasq on ipv4 it'll provide forward/reverse lookups by default for dhcp clients.



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