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Re: consensus call of RR prefix




terry@xxxxxxxxxxxxxxxxxxxx wrote:

-not all dns servers support "_"

Just for clarification: Which DNS servers do /not/ support underscores?

I know from testing that BIND 9 is happy with them; since Microsoft uses them for some AD stuff, I guess that at least newer implementations of their DNS services will not choke on them.

Local DNS libraries seem to be able to handle it - at least I haven't heard of resolver-library incompatibility with products that use Apple's Rendezvous, which is based on kind-of-SRV records and also use SRV's _<service>._<proto> scheme.

Of course, further testing would be fine, but technically most relevant pieces of DNS software around should not have issues underscores.


-many dns providers do not allow subdomains (or not easily via an interface, and we need to keep
publishing easy or it won't get done)(yes I know many ISPs don't support TXT RR either, but that
*is* changing and it *is* an RFC compliant DNS standard, even if SPF abuses it)

Which DNS providers do (not) allow subdomains and/or TXT records?

Adding something a record for "_spf" should not be any different from adding a "www" record to a domain.

(Adding TXT records to the admin GUI of my non-profit ISP took me a couple of minutes.)

IMO, there are no technical or admin issues for or against RR prefixes. Having said that, there are of course policy reasons to consider - eg if we go for a dedicated record type for "MARID", there is no need for a prefix (after all, we don't have a prefix for MX records).

Still IMO, a prefix would only make sense if the TXT record workaround were a long-term solution. As this quite possibly is not the intention of this working group, using a prefix does not offer any benefits other than possibly keeping the DNS response size below the magical 418 bytes, a restriction which can be easily worked around using redirects by those few(?) that would need it.

-- Matthias

--
Brain-Log                               http://matthias.leisi.net/