It's dpkt.ethernet.Ethernet(pkt)
for an ethernet interface, what is it for the ppp0
interface?
You're mixing up dpkt, a library for parsing and creating packets, with pypcap, a Python wrapper for libpcap.
To specify an interface to listen on, use pcap.pcap(name='ppp0')
.
To deserialize PPP packets, use dpkt.ppp.PPP(pkt)
.