实时流量监控
display bandwidth usage on an interface by host
iftop -h | [-nNpblBP][-i interface] [-f filter code][-F net/mask] [-G net6/mask6]
-h Print a summary of usage.
-n Don't do hostname lookups.
-N Do not resolve port number to service names
-p Run in promiscuous mode, so that traffic which does not pass directly through the specified interface is also counted.
-P Turn on port display.
-l Display and count datagrams addressed to or from link-local IPv6 addresses. The default is not to display that address category.
-b Don't display bar graphs of traffic.
-m limit
Set the upper limit for the bandwidth scale. Specified as a number with a 'K', 'M' or 'G' suffix.
-B Display bandwidth rates in bytes/sec rather than bits/sec.
-i interface
Listen to packets on interface.
-f filter code
Use filter code to select the packets to count. Only IP packets are ever counted, so the specified code is evaluated as (filter code) and ip.
-F net/mask
Specifies an IPv4 network for traffic analysis. If specified, iftop will only include packets flowing in to or out of the given network, and packet direction
is determined relative to the network boundary, rather than to the interface. You may specify mask as a dotted quad, such as /255.255.255.0, or as a single
number specifying the number of bits set in the netmask, such as /24.
-G net6/mask6
Specifies an IPv6 network for traffic analysis. The value of mask6 can be given as a prefix length or as a numerical address string for more d bitmask‐
ing.
-c config file
Specifies an alternate config file. If not specified, iftop will use ~/.iftoprc if it exists. See below for a description of config files
-t text output mode
Use text interface without ncurses and print the output to STDOUT.