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

Stefan Hajnoczi stefanha at gmail.com
Thu Nov 27 08:01:21 PST 2008


> Thanks for the patch but I believe the behavior isn't quite as expected.
Thanks for explaining and giving a valid example.  Is there a
definitive reference (an RFC?) which describes the resolver algorithm?

> This method suggested would cover both cases and you can't assume
> no dots is not a FQDN http://com/  is valid, technically.
I don't agree with this point.  The name "com" is not absolute.  I
think you mean "com." which is rooted and absolute.
[http://tools.ietf.org/rfc/rfc1535.txt]

Stefan

On Thu, Nov 27, 2008 at 3:25 PM, Kevin Landreth
<crackerjackmack at gmail.com> wrote:
>
>
> On Thu, Nov 27, 2008 at 9:21 AM, Kevin Landreth <crackerjackmack at gmail.com>
> wrote:
>>
>> 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
>>
>> Attempt to resolve hostname
>> NXDOMAIN response, and only NXDOMAIN,
>>
>> Does <domain-name> from DHCP exist?
>>
>> If so, append <domain-name> from DHCP settings, if it exists
>>
>> If not, goto 4
>>
>> re-attempt to resolve the domain name
>> 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
>>
>
>
> I should also note that the current behavior IS correct, just limited in
> scope :)  This method suggested would cover both cases and you can't assume
> no dots is not a FQDN http://com/  is valid, technically.
>
> --
> Kevin Landreth, RHCE
>
>




More information about the Syslinux mailing list