16 Dub
2015
16 Dub
'15
17:34
Hi Anand,
On 16 April 2015 at 16:45, Anand Buddhdev <anandb(a)ripe.net> wrote:
Dear Knot developers,
In Knot 1.6.3, is it safe to leave out the "interfaces" section of the
config on a multi-homed server? Will Knot enumerate all the addresses on
the host and bind to them, or will it bind to 0.0.0.0 and ::?
it's safe, but then it will do exactly that and it will start
listening on nothing.
There is no automagic default.
Secondly, if bound to 0.0.0.0 and ::, will Knot use
recvmmsg correctly
and set the source address in UDP reply packets to the address the query
was sent to?
it may and it may not, this applies for both recvmmsg/recvmsg backends.
The thing is that while ANY works well for TCP, since each connection gets a new
socket with correctly set endpoints, it is not like that for UDP and
the application
has no* control over the source address. _Usually_ the operating
system selects the
right address (right meaning "most appropriate"), but it shouldn't be
relied upon.
Your best bet is to template it, since there are no variables in the
configuration,
or stick with the ANY but don't rely on the outgoing address for
things like ACLs and such.
Maybe someone else has a better idea?
Marek
* At least not portable.
Regards,
Anand
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