SRV RR
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The SRV RR allows administrators to use several servers for a single
domain, to move services ...
... The format of the SRV RR ...
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Here is the format of the SRV RR, whose DNS type code is 33:
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... The domain this RR refers to. The SRV RR is unique in that the
name one searches for is not this name; the example near the end
shows this clearly.
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... random number selected. The target host specified in the
selected SRV RR is the next one to be contacted by the client.
Remove ...
... update their client applications when the first
server publishes a SRV RR is futile (even if desirable). Therefore
SRV would have to coexist with address ...
... the same DNS node as the SRV RR, listing reasonable (if perhaps
suboptimal) fallback hosts for Telnet ...
... overhead plus the name
of the service ("_ldap._tcp.example.com" for instance); each SRV RR
adds 20 bytes plus the name of the target host; each NS ...
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If the reply is NOERROR, ANCOUNT>0 and there is at least one
SRV RR which specifies the requested Service and Protocol in
the reply:
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... Select an element as specified above, in the
description of Weight in "The format of the SRV
RR" Section, and move it to the tail of the new
list
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... If the Additional Data section doesn't contain address records
for all the SRV RR's and the client may want to connect to the
target host ...
... 20 bytes for the query string, "_foobar._tcp.example.com."
130 bytes for 4 SRV RR's, 20 bytes each plus the lengths of "new-
fast-box", "old-slow-box", "server" and "sysadmins-box" -
"example.com" in the query ...