Is there a way to have ntopng ignore traffic between local interfaces?

[ryan87]

Even with historical data disabled, ntopng uses a lot of disk space for me.  For example:

date && du -chs /var/db/ntopng

Thu Feb 18 20:02:09 CST 2016
4.6M	/var/db/ntopng
4.6M	total

Thu Feb 18 23:17:07 CST 2016
 42G	/var/db/ntopng
 42G	total

That's 10GB+ per hour.  I suspect it's because I have 2 LANs.  I haven't tested it thoroughly, but it seems like large jumps in disk usage coincide with transferring large files between LANs.

I've read that ntopng will take a libpcap filter using a –packet-filter option.  Does anyone know if it's possible to pass a libpcap like filter to ntopng in pfSense?