So like the title says, I logged into my server and I noticed last and lastb seem to have been reset sometime before 00:48 after the new year. Is this intentional to have it reset, or does it only display the current year's? Or should I be concerned that someone has gotten access to my server? I do have SSH and HTTP port forwarded out of my network - so it's a live server. 
Debian Linux - Ubuntu - Logs cleared for last and lastb, but not /var/log/auth.log after new year
debian
The last and lastb commands read /var/log/wtmp and /var/log/btmp respectively. These logs are rotated by logrotate which has is configured in /etc/logrotate.conf and /etc/logrotate.d. The rotation of the two files of interest is managed by the main configuration file. For /var/log/wtmp I have:/var/log/wtmp {    missingok    monthly    create 0664 root utmp    rotate 1}This means that every month /var/log/wtmp will be  moved to /var/log/wtmp.1. So, this is nothing to worry about - to access the old log, just do:last -f /var/log/wtmp.1