[syslinux] [Etherboot-developers] gPxe functionality in pxelinux

[Kevin Landreth]

On Thu, Nov 27, 2008 at 3:26 AM, Stefan Hajnoczi <stefanha at gmail.com> wrote:

> > Is there any way to get it to honor the 'domain-name' setting from DHCP
> and do a dns search like the libc resolver does for resolv.conf ?
>
> The following patch appends the DHCP Domain Name setting to relative
> names.  Any name with one or more "." is considered qualified and is
> not affected.
>
> DNS experts, please advise whether this is correct!  Pointers to the
> relevant RFCs or source appreciated.
> [snip]
>
>
Thanks for the patch but I believe the behavior isn't quite as expected.  It
only works in one case where a host with no '.' (dots) is appended with
<domain-name>.

The behavior should be as follows

   1. Attempt to resolve hostname
   2. NXDOMAIN response, and only NXDOMAIN,
   1. Does <domain-name> from DHCP exist?
         1. If so, append <domain-name> from DHCP settings, if it exists
      2. If not, goto 4
      3. re-attempt to resolve the domain name
   4. fail if not found (not just NXDOMAIN, any DNS failure)

Here is a case where the current patch would not behave as expected:

kernel http://repo-server.development/path/to/kernel
wouldn't be appended with the localized DHCP setting of <domain-name> =
dllstx03.internal.bigcorporation.net

I've seen this setup in many places, though not related to net booting, but
how clients work and expect the environment to behave.  True that this might
not be the most optimal setup but it is what it is :(

-- 
Kevin Landreth, RHCE