IPv6 and IPv4 - how to shut off IPv6?

[Ben Scott]

On 4/1/07, Bruce Labitt <bruce.labitt at verizon.net> wrote:
> As a result of the mythfest install, my computer was setup with FC6.

  I might argue that should be "In spite of the mythfest install...".  ;-)

> I do know that my router does not like to pass through IPv6 info, so I am
> suspecting something like this.

  You can disable IPv6 networking by editing the file
</etc/sysconfig/network> and changing or adding the line
<NETWORKING_IPV6=no>.  Then run <service network restart>.  (Don't
type the angle brackets in any of this.)  You will need root
privileges for this, so use "su", "sudo", etc., as needed.)

> Are there some tools I can use to determine what is actually happening?

  Dave's (aluminumsulfate) suggestions are good.  You may also want to
compare the times for the following commands:

host liberty.gnhlug.org
ping -n 199.125.75.42
ping -n liberty.gnhlug.org

  The first command (host) does just a DNS lookup.  The second command
pings the GNHLUG web server by IP address, suppressing all name
lookups (-n).  The third command pings the GNHLUG web server by name,
suppressing all other name lookups.  If the first command takes a long
time to complete but the second goes quickly, there is a problem with
your DNS configuration.  If both are slow, that implies a general
network or local system problem.   If only the third command is slow,
that implies a local nsswitch problem (since DNS was fast).

-- Ben