[lug] Backup

[Siegfried Heintze]

Boot server? Boy am I ignorant! I've never heard of boot server before. Does
that $100 Linksys NAS server (what is the model number again?) that Bear was
telling me to hack into a NFS server qualify as a boot server? Can I do a
network boot with the DHCP built into a typical $50 router/firewall/nat and
the $100 Linksys NAS server?

Oh -- and incidentally: If one hacks that NAS server to serve NFS instead of
SMB/CIFS, can you load a samba server on it too so it will allow both
windows and linux to network boot? That would be handy. 

The only firewalls I know of are my linksys opewrt/WRT54G firewall I just
installed and the firewalls built into linux and windows. I can control
those.

So can I buy a service that would let me network boot across the public
internet and then restore the entirety of my bootable linux and windows
paritions using rdiff or rbackup? Anyone have a URL?

Now if someone were to start such a service, what ports would they have to
open up in their firewall? I wonder if that guy with the massive media safe
would be willing to provide a network boot repository for me?

Now how would one restore a bootable NTFS partition? Network boot from Linux
and mount the NTFS partition as writable (yeah, I know, you are not supposed
to do that but assuming a hacker as typed fdisk, you have nothing to loose)
and then use rdiff, or rsync or rbackup?

Or, could I network boot windows across the internet and then use windows to
restore the partition? Hmmm... this may be the wrong mailing list to discuss
this issue (no rotten tomatoes please!) But surely I'm not the only one who
has a dual boot linux/windows machine! Maybe http://www.nu2.nu/pebuilder/
has some answers for me.

Thanks for all the info, guys!

Siegfried

> Bear Giles wrote:
> > Siegfried Heintze wrote:
> > 
> >> Is it possible to do a network boot thru a firewall from an internet 
> >> on someone else's machine?
> > 
> > No.  I don't recall the details on "PXE", but "BOOTP" is essentially 
> > DHCP with an additional payload that specifies where the hardware can 
> > download (via TFTP) a boot image.
> 
> Bear is incorrect, except in the case of using bootp (like Sun's
> jumpstart).
> 
> When a PXE machine boots off the network it gets its IP address from
> DHCP.  The DHCP server can also serve it a boot server and image path
> that PXE will use to download the kernel image, load it, and boot it.
> 
> DHCP, even though it is a broadcast protocol, can be relayed across
> routers.  ISC's suite of DHCP software will do this.  Cisco has a
> "DHCP helper" or some such that does the same thing.  So does
> Microsoft.  So as long as there's a relay agent on your subnet the
> DHCP server can be anywhere.
> 
> The kernel image is downloaded with TFTP, which is a typical point to
> point protocol using TCP.
> 
> The problem with bootp is that it is an earlier form of DHCP and
> doesn't provide the extensions needed to relay it.  So it only works
> on the local subnet.  (Sun's jumpstart requirements list a bootp
> server for each subnet.  Jumpstart can use DHCP but that isn't the out
> of the box way to do it.)
> 
> Whether you can do all this through various firewalls depends entirely
> on their security policies and whether they allow it (and are
> configured to implement that part of the policy correctly).
> 
> Dave
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