Mats Erik Andersson <[email protected]> writes: > This behaviour is present if GNU Inetutils is compiled with IPv6 support: > > $ ./src/logger -6 -h gnu.org -p user.debug Testing IU-logger > ./src/logger: no address associated with name, gnu.org:syslog. > > $ echo $? > 1 > > It is in a situation where compilation was done without IPv6 support, > that the logger client takes the liberty of ignoring `-6', uses IPv4, > sends the message, and emits a warning for the user. Thus it is really > single stacked IPv4-machines that are expected to rescue the user. > On all up to date machines the options `-4' and `-6' will abort with > errors if the host, port, and source are not able to fit the chosen > domain.
Ah, right. How does 'telnet' behave if IPv6 is not supported and the user provides -6? >> >> Typically users won't use --ipv4 or --ipv6 but rather use a hostname, >> and let the getaddrinfo() do its magic of selecting ipv4 vs ipv6, right? > > This is an important point. Presently I have set AF_UNSPEC when both > flags are missing (and the compilation had "#define HAVE_IPV6 1"). > Since UDP is carrying the message, this means that any dual stacked > host with existing A and AAAA DNS-entries might be contacted via a > domain where the syslog service does not listen, if it was set up > in an asymmetric manner. > > Can it be argued that AF_INET still should be the default? > Bearing in mind that the migration to IPv6 is still in its > beginning. I do not know for certain yet. I suspect we won't know the best long-term solution here, but I mildly prefer AF_UNSPEC too but realize that some people may find that problematic. /Simon
