Re: Late to the party - multiple search domains on the network.

[Dan Williams <dcbw redhat com>]

On Sun, 10 Apr 2005, Simon Kelley wrote:
> I just found NetworkManager this weekend whilst researching how to solve 
> the problems that NetworkManager solves. It looks good and I plan to 
> work with it.

Great!  The larger the party the better.

> I came across 
> http://mail.gnome.org/archives/networkmanager-list/2005-February/msg00122.html 
> in the archive: quote
> 
>  >When the "domainName" DHCP option contains spaces, nm-named-manager
>  >proclaims it as invalid, although multiple domain names are often used
>  >in the DHCP server configuration. The attached patch fixes this
>  >behavior.
> 
> It's worth knowing that putting multiple space separated domain names in 
> DHCP option 15 is _not_ the correct way to do this.  I know that people 
> do it (because the ISC code _still_ doesn't support the correct way, 
> AFAIK) but it will break much of the time. (Even if you fix it on Linux, 
> the Windows and Mac boxen on your network will choke.)
> 
> The correct way is to use DHCP option 119, as defined in RFC 3397. The 
> data format is not a simple counted string, but a variant on the format 
> used in DNS packets, complete with common substring elimination. I guess 
> those IETF people where worried about the size of their packets.
> 
> The Debian package for dhcpcd includes a patch to support option 119. I 
> submitted the patch upstream, but the mail bounced repeatedly - looks 
> like the dhcpcd maintainer is MIA. I'm happy to try an work out a patch 
> for the NM-included dhcpcd too, if that would help.

I was never able to contact the maintainer, and the code in NetworkManager for 
dhcpcd is based on the latest Mandrake code since it had a few patches that 
looked like they did good things.

Note that at some soon point we're going to switch to using dhclient rather than 
our internal DHCP client.  Jason VasDias at Red Hat is adding in the support to 
dhclient that would be required to use it with NetworkManager.  That should fix 
up most compatibility problems too.

Dan