少し古いので最新のlibpcapをインストール
$ yum list | grep libpcap
libpcap.x86_64 14:1.4.0-1.20130826git2dbcaa1.el6
libpcap.i686 14:1.4.0-1.20130826git2dbcaa1.el6
libpcap-devel.i686 14:1.4.0-1.20130826git2dbcaa1.el6
libpcap-devel.x86_64 14:1.4.0-1.20130826git2dbcaa1.el6
$ yum install flex bison
$ wget http://www.tcpdump.org/release/libpcap-1.7.3.tar.gz
$tar zxvf libpcap-1.7.3.tar.gz
$ cd libpcap-1.7.3
$ ./configure
$ make
$ make install