On 1 Apr 2008, at 16:36 , Andrew Sullivan wrote: > On Tue, Apr 01, 2008 at 10:36:28AM -0400, Edward Lewis wrote: > >> Multiple PTR records can be stored in a single PTR RRset. If a >> device at an IP address (v4 or v6) has multiple identities with >> domain names, it would be good to have a PTR for each. However, this >> is not always practical. In some operational situations, an address >> may have thousands of domain names holding an address record (A or >> AAAA) with the address as the value.
How about re-writing the last sentence as "In some operational situations, a single address might be used as RDATA for a large number of A or AAAA resource records." >> The number of address records in an PTR set before tripping the upper >> limit on what can fit on even a TCP carried DNS message is >> approximately 4000 for A RR only and about 2000 for AAAA RR only. "The maximum size of a DNS message is 65536 bytes [RFC1035]. The number of resource records in a single PTR RRset is correspondingly limited." (The limit is surely a function of the average encoded size of RDATA for the PTR records in the RRset, and has nothing to do with whether the PTR record lives under in-addr.arpa or ip6.arpa?) >> If an address has just a few corresponding forward map records, it is >> worth entering them all. If an address has many, a better strategy is >> to enter a few as is needed, adding more only when there is an >> operational request. I don't see value in adding the text above. Joe _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
