It is possible to received an error in syslog when you start snort 2.6

‘Not Using PCAP_FRAMES’

This message can be ignore if you don’t have any performance issue. If you run snort on a slow machine or have a lot of packets to analyzes or are dropped, follow this post

Snort 2.6 does not compile correctly on Fedora core 5.

Here is what you have to do to compile it:
./configure --with-mysql --enable-dynamicplugin
make
make check
libtool --finish /usr/local/lib/snort_dynamicpreprocessor
make install

Taken from this post