To analyze the captured traffic we need some tools.
I prefer the commandline interface and use the programm tshark for this.


to only read pcap files use

> tshark -r ethernet_traffic.pcap

use display filter (-Y) for wireshark filter syntax

## filter by ip adresses
> tshark -r ethernet_traffic.pcap -Y "ip.addr == 10.10.0.18"
## exclude port 80
> tshark -r ethernet_traffic.pcap -Y "tcp.dstport != 80"
## show only http and icmp traffic
> tshark -r ethernet_traffic.pcap -Y "tcp.port eq 80 or icmp"
## show only traffic in lan 10.10.x.x
> tshark -r ethernet_traffic.pcap -Y "ip.src==10.10.0.0/16 and ip.dst==10.10.0.0/16"

NOTE: and, or, (), and ! are used to combine statements
for more filter examples see: wireshark wiki

some nice oneliner

## pipe pcap file to awk to only show the captured ip addresses
> tshark -r ethernet_traffic.pcap  | \
awk '{ print gensub(/(.*)\..*/,"\\1","g",$3), $4, gensub(/(.*)\..*/,"\\1","g",$5) }'
## if there a lot of dupes append another awk pipe
> awk '!NF || !seen[$0]++'