Missing backups from Time Machine A have a MacBook running Mountain Lion that backups up to a Linux machine over afp (netatalk) using Time Machine. 

In Time Machine preferences I can see that the Oldest backup was on 5th March 2012 (a year). If I go to 'Enter Time Machine' I can old go far back as 4th of March 2013 (a week). Using the 'tmutil' command I can see 43 backups from 2012 until an hour ago. 

There has never been a problem with space on the Linux machine and there has been little change to settings or software on either computer for over a week. 

Is there a way I recover from these missing backups? How can I prevent this occurrence from happening again? I do not need anything from this backup at the moment but I still want the ability to do so.

[EDIT] So one of the comments below got me thinking. There are two interfaces on this computer. One is set statically with a hostname and IP address, the other is by DHCP and takes the default Mac OSX hostname.
I suspect based on the comments, that Mike Meyers has a point, in that you are only seeing  MobileBackups, and that tmutil is simply showing you pointers (or logs) to the Time Machine backups on the linux server. For some reason the actually backup on the drive is not readable by Time Machine. I suggest dumping the network drive to an external, OS Extended Journaled hard drive and see if you can point Time Machine to that.