Maintained by: NLnet Labs

[Unbound-users] Query over 'forward-addr' / 'forward-first'

Karl Pielorz
Sat Jul 14 00:17:06 CEST 2012


Hi All,

I've just started looking at Unbound, under FreeBSD 9, currently running 
unbound 1.4.17.

I have three 'local' nameservers on our LAN, and I've been using:

"
forward-zone:
        name: "."
        forward-addr: 1.1.1.1
        forward-addr: 2.2.2.2
        forward-addr: 3.3.3.3
        forward-first: yes
"

[obviously 'example' IP's!]

This seems to work fine - i.e. under normal circumstances, queries are 
answered fine. If I deliberately "fail" 1.1.1.1 - queries are still 
answered, ditto if I fail 2.2.2.2 as well - they are all sent to 3.3.3.3 to 
be resolved, and the system can still resolve names.

In 1.4.17 how are forwarders selected? - From syslog/verbose logging - it 
appears it latches onto one, and stays with it (maybe the fastest 
responder?)

Is there any way of seeing (e.g. from 'unbound-control dump_infra') which 
forwarders it considers 'available' or 'not available' / down?

Also, can someone clarify what 'forward-first' actually means? - In the man 
page it says:

"If  enabled,  a query is attempted without the forward clause if
              it fails.  The default is no."

With this set to 'yes' - if I fail all the forwarders, nothing gets 
resolved (I was kind of expecting it to retry the query - with the roots? - 
i.e. no forwarders?) - or does this not apply if you're trying to forward 
"."?


Thanks for your time,

-Karl