Tool 11: Sniff and verify checksums
Description:
This tool sniffs and verify checksums (IP header, TCP, UDP, etc.).
If a bad checksum is encountered, it is displayed along with the
expected value.
Parameter --device indicates on which device to sniff. Please note
that under some systems, such as Windows, sniffing on some devices is
not supported.
Parameter --filter defines the sniff filter. It permits to restrict
captured packets. This kind of filter is named a BPF or pcap filter.
Basic elements of a filter are:
host 1.2.3.4
net 192.168.10
net 192.168.10.0 mask 255.255.255.0
net 192.168.10.0/24
port 21
dst host 1.2.3.4
src port 2345
ether host a:b:c:d:e:f ('ether a:b:c:d:e:f' is not working)
ether src aa:bb:cc:dd:ee:ff
ip
arp
rarp
tcp
icmp
udp
Here are filter examples:
"host 1.2.3.4"
"net 192.168 and icmp"
"host 1.2.3.4 or dst port 80"
"(udp or tcp) and not host 1.2.3.4"
Parameter --rawip indicates to ignore Ethernet/link layer, and start
displaying at IP header.
Parameter --ipreas tries to reassemble IP packets. This might miss
packets.
This tool may need to be run with admin privilege in order to sniff.
Synonyms:
capture
Usage:
netwox 11 [-d device] [-f filter] [-r|+r] [-i|+i]
Parameters:
parameter |
description |
example |
-d|--device device |
device name |
Eth0 |
-f|--filter filter |
pcap filter |
|
-r|--rawip|+r|--no-rawip |
sniff at IP level |
|
-i|--ipreas|+i|--no-ipreas |
reassemble IP packets |
|
Example:
netwox 11