Default iptraf build that comes with RedHat or CentOS does not support bondX interfaces, or vlan (ethX.Y) interfaces, however there's a version on bugzilla.redhat.com that does support it. More details: https://bugzilla.redhat.com/show_bug.cgi?id=441081 Also, for you the lazy ones out there, quick install procedure (done on CentOS5 x86_64) :
#remove current iptraf version
root@host ~# yum remove iptraf
root@host ~# wget "https://bugzilla.redhat.com/attachment.cgi?id=304745" -O iptraf-3.0.0-6.el5.src.rpm
root@host ~# rpmbuild --rebuild iptraf-3.0.0-6.el5.src.rpm
root@host ~# rpm -Uvh /usr/src/redhat/RPMS/x86_64/iptraf-3.0.0-6.x86_64.rpm
Ready to go.
If there's no rpmbuild command, install rpm-build, and also you'll
have to add some packages like ncurses-devel