[syslog-ng] 'network' Destination With Hostname Resolution (IPv4 vs IPv6)

[David Hauck]

Hi,
 
Thought I would reach out again to see if anyone had any thoughts on the item below.
 
Thanks for the consideration,
-David
 
On Wednesday, September 12, 2018 3:39 PM, syslog-ng <syslog-ng-bounces at lists.balabit.hu> On Behalf Of David Hauck wrote:
> Hi,
> 
> I have a question regarding how to specify a network destination when using a hostname when the
> hostname can be resolved to either IPv4 or IPv6. In particular what should be specified by the ip-
> protocol() parameter? There are some configuration scenarios and/or target installations that don't
> know a priori whether the DNS configuration will resolve to an IPv4 or IPv6 address.
> 
> E.g.,
> 
> destination d_tcp6 {
>     network(
>         "myhost"
>         port(514)
>         transport(udp)
>         ip-protocol(6 or 4 or ??)
>         );
> };
> 
> It seems like it would simple enough to have syslog-ng simply validate the resulting IP address string to
> determine which of ip-protocol(4) or ip-protocol(6) is actually needed. In fact, I would argue that
> specifying an IP address string (as the "<destination-address>" value) could result in the same
> determination (the address string necessarily unambiguously determines whether the reference is an
> IPv4 or an IPv6 address and I would think there is a 1-1 relationship between this determination and
> whether ip-protocol(4) or ip-protocol(6) is used - (in other words it would never make sense to have
> these mixed: "::1" and ip-protocol(4) would be invalid).
> 
> Thanks, -David
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