SRV records and "_"

[Barry Margolin]

In article <93g2p4$g7c at pub3.rc.vix.com>, none <foo at bar.com> wrote:
>RFC 2782 suggests using the underscore, "_", character to prepend service
>identifiers in order to avoid collisions with naturally occurring hostnames.
>Example:
>
>_smtp._tcp  600  IN SRV 1 0 25   smtp.domain.com.
>
>Is this legal in any version of BIND ? Are there any network clients that

It should be legal in all versions since SRV was created.  Underscores are
only restricted in hostnames, not any other context.

>query for SRV records with which to test? I have tried testing using
>'nslookup -q=srv domain.com' and it appears to accept srv as a valid
>querytype, but I get no info back, either with or without the underscore.

The query you show above shouldn't return anything, since the SRV record
isn't attached to the name domain.com.  You have to do something like:

nslookup -q=srv _smtp._tcp.domain.com

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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