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

[David Hauck]

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