Backup Central

The laptops I back up have both a wired and wireless Ethernet
connection with (different) MAC addresses.

I use static DNS so that when the laptops are attached at home they
are given a fixed (known) IP address so that BackupPC can find them
using my /etc/hosts file.

On my old D-Link router, I used to assign the same static DNS address
to both MAC addresses so that no matter which connection was used, I
had the same fixed IP address.

The problem is that my new Verizon router does not allow the same IP
address to be correlated with different MAC addresses.

So now it seems that I can only match the laptop name (used by
BackupPC) against only one of the IP addresses so that it will only
get backed up on one of the two interfaces?

Is there any simple way to overcome this problem?

For example would it be possible to match 2 IP/names addresses against
the same host backup so that if one fails then it tries the other?
(this is in a sense the opposite of ClientNameAlias that allows you to
map multiple hosts to one IP address)

------------------------------------------------------------------------------
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
_______________________________________________
BackupPC-users mailing list
BackupPC-users < at > lists.sourceforge.net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/

"Jeffrey J. Kosowsky" <backuppc < at > kosowsky.org> wrote on 01/16/2012 05:00:45 PM:

The problem is that my new Verizon router does not allow the same IP
address to be correlated with different MAC addresses.

So now it seems that I can only match the laptop name (used by
BackupPC) against only one of the IP addresses so that it will only
get backed up on one of the two interfaces?

Is there any simple way to overcome this problem?

You could:

1) Use a better (real) Firewall

That would be, by *FAR*, the best solution. Other solutions:

2) Use a better (real) DNS server with client-update capabilities (See #1)
3) Use a better (real) DHCP server (See #1)

These are really just more specific details embodied by #1. Now that I've beat that dead horse...

4) Use NetBIOS name resolution. (This merely lets you substitute a completely *different* and hopefully less broken name server infrastructure. See #1... )

For example would it be possible to match 2 IP/names addresses against
the same host backup so that if one fails then it tries the other?
(this is in a sense the opposite of ClientNameAlias that allows you to
map multiple hosts to one IP address)

Why fix an IP routing/name resolution issue at the BackupPC level? Fix it where the problem is, rather than paper over it. While 'another layer of indirection can fix anything' (http://en.wikipedia.org/wiki/Indirection , second paragraph), it doesn't mean that it *should*! If you want to go that way, there's always

5) Create two BackupPC hosts, one for each of the IP addresses your Verizon DHCP server will be assigning to the client...

And then, knowing your ability to create great little Perl utilities to manipulate the BackupPC pool:

6) Create a tool to merge the backups of one host into the other...

Tim Massey

P.S.: In case it doesn't come across in text: I give you honest, serious, mad props for your Perl code that manipulates the pool, though I personally am very reluctant to use them. However, I still think you need to fix this problem where the problem actually *is*, rather than paper over it with BackupPC mangling.
T.J.M.
Out of the Box Solutions, Inc.
Creative IT Solutions Made Simple!
[url=Arial]http://www.OutOfTheBoxSolutions.com[/url]
[url=Arial]tmassey < at > obscorp.com[/url] 22108 Harper Ave.
St. Clair Shores, MI 48080
Office: (800)750-4OBS (4627)
Cell: (586)945-8796

Jeffrey J. Kosowsky wrote at about 17:00:45 -0500 on Monday, January 16, 2012:
The laptops I back up have both a wired and wireless Ethernet
connection with (different) MAC addresses.

I use static DNS so that when the laptops are attached at home they
are given a fixed (known) IP address so that BackupPC can find them
using my /etc/hosts file.

On my old D-Link router, I used to assign the same static DNS address
to both MAC addresses so that no matter which connection was used, I
had the same fixed IP address.

The problem is that my new Verizon router does not allow the same IP
address to be correlated with different MAC addresses.

So now it seems that I can only match the laptop name (used by
BackupPC) against only one of the IP addresses so that it will only
get backed up on one of the two interfaces?

Is there any simple way to overcome this problem?

For example would it be possible to match 2 IP/names addresses against
the same host backup so that if one fails then it tries the other?
(this is in a sense the opposite of ClientNameAlias that allows you to
map multiple hosts to one IP address)


Just was thinking that the following simple hack should probably
work...

1. Set up two different static IPs, one for each network interface.
2. Enter both IPs (or equivalent names as defined in /etc/hosts) in
the BackupPC/hosts file -- call them 'hostA' and 'hostB'
3. Create a *symlink* from TopDir/pc/hostB to TopDir/pc/hostA

Then whenever the *common* backup host ages, BackupPC will launch a
new backup -- either hostA or hostB depending on which NIC is
currently active (note: I am assuming that only one interface is
active at a time). That way if one IP addressdidn't back up then the
other would back up in place using the same history of numbered full
and incremental backups. Once either backup completed then both hosts
would look updated since they both point to the same common pc host
subdirectory of backups. Note that the host name doesn't appear at all
except as the name of the top level directory in the pc tree, so it
makes no difference whether the backup is initiated as hostA or
hostB.

The only potential issue would be collisions but even that typically shouldn't
happen since I assume that only one IP address is ever active at one
time. Potentially there might be issues if the user switched interfaces in
the middle of a backup before the first version complete or timed out
but hopefully the new backup would catch the other as a partial backup
and either continue from there or erase it... still I imagine there
could be weird edge cases though they would only occur if you switched
network interfaces mid-backup...


------------------------------------------------------------------------------
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
_______________________________________________
BackupPC-users mailing list
BackupPC-users < at > lists.sourceforge.net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/

On Mon, Jan 16, 2012 at 5:32 PM, Jeffrey J. Kosowsky
<backuppc < at > kosowsky.org> wrote:

 > 1) Use a better (real) Firewall
 >
 > That would be, by *FAR*, the best solution.  Other solutions:
 >
 > 2) Use a better (real) DNS server with client-update capabilities (See #1)
 > 3) Use a better (real) DHCP server (See #1)

You certainly have a good point in theory and that would be the
correct approach for a larger/more formal network. But for me, it's
just a simple home network... I really don't want to start adding a
new/separate firewall and/or DNS and/or DHCP layer just to get
BackupPC to run when everything runs just fine using my
Verizon-provided router as router/firewall/gateway/dns/dhcp etc. (I do
have a software firewall also on each machine).

Have you checked all the capabilities? Lots of consumer routers have
local DNS service with update capability - or at least the ability to
specify a name with the IP for DHCP.

Also, do you plug the laptop in regularly anywhere else? Maybe you
could do a static assignment on the wired port but don't activate it
anywhere else - and then keep the DCHP assignment for the wifi side.

 > 4) Use NetBIOS name resolution.  (This merely lets you substitute a
 > completely *different* and hopefully less broken name server
 > infrastructure.  See #1...   )

Same reasoning as above... And I really would like to avoid NetBIOS
since I don't even have it running on my Linux machines...

You could probably run nmbd without smbd. Nothing would depend on it
except fallback name resolution.

 > 6) Create a tool to merge the backups of one host into the other...  
 >

Well, I appreciate your confidence, but that would be a real PITA.
That being said, I do at some point intent plan on writing just such a
utility that a more general level allows for the merging of two
different pools... but I haven't had the time

Wonder what would happen if you symlinked two pc names. I don't think
I want to find out on my system, but...

Again, if I were running a large network or a production server, I
would totally agree with you.

But it might just be simpler, easier, and cleaner for me to hack the
BackupPC code so that if one host ip name/number then it tries
another...

One other approach that would work would be to set up a VPN between
the backuppc server and targets using OpenVPN or something similar.
Normally you'd only need that to poke through firewalls or route
between private networks, but you can end up with a known IP at the
tunnel interface regardless of the networks/interfaces the packets
carrying the tunnel traverse.

--
Les Mikesell
lesmikesell < at > gmail.com

------------------------------------------------------------------------------
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
_______________________________________________
BackupPC-users mailing list
BackupPC-users < at > lists.sourceforge.net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/

On Mon, Jan 16, 2012 at 6:43 PM, Jeffrey J. Kosowsky
<backuppc < at > kosowsky.org> wrote:
 >
 > Also, do you plug the laptop in regularly anywhere else?  Maybe you
 > could do a static assignment on the wired port but don't activate it
 > anywhere else - and then keep the DCHP assignment for the wifi
 > side.

True - but I would like the backups to 'just' work whether using the
wired or wireless ports. For now, I have the static assignment set for
the wireless NIC since that is what people used most... but sometimes
you actually prefer to use the wired NIC, especially for backup, since
the link speed is faster.

I meant do the static assignments on the laptop side for the wired
interface, unless you use the wired connection elsewhere enough to be
a problem. Then you only need one setting on the router.


 > One other approach that would work would be to set up a VPN between
 > the backuppc server and targets using OpenVPN or something similar.
 > Normally you'd only need that to poke through firewalls or route
 > between private networks, but you can end up with a known IP at the
 > tunnel interface regardless of the networks/interfaces the packets
 > carrying the tunnel traverse.
 >

Interesting thought but probably overkill, especially since the
laptops are pretty slow...

But once set up, you could use router port-forwarding to let it work
from anywhere. And there's not that much overhead from OpenVPN.

--
Les Mikesell
lesmikesell < at > gmail.com

------------------------------------------------------------------------------
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
_______________________________________________
BackupPC-users mailing list
BackupPC-users < at > lists.sourceforge.net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/