embedaddon/iftop/iftop.cat - view

File: [ELWIX - Embedded LightWeight unIX -] / embedaddon / iftop / iftop.cat
Revision 1.1.1.2 (vendor branch): download - view: text, annotated - select for diffs - revision graph
Tue Oct 18 14:04:50 2016 UTC (8 years, 2 months ago) by misho
Branches: iftop, MAIN
CVS tags: v1_0rc4, HEAD

iftop 1.0pre4

IFTOP(8) IFTOP(8) -e .pl 1100i NNAAMMEE iftop - display bandwidth usage on an interface by host SSYYNNOOPPSSIISS iiffttoopp --hh | [--nnNNppbbllBBPP] [--ii _i_n_t_e_r_f_a_c_e] [--ff _f_i_l_t_e_r _c_o_d_e] [--FF _n_e_t/_m_a_s_k] [--GG _n_e_t_6/_m_a_s_k_6] DDEESSCCRRIIPPTTIIOONN iiffttoopp listens to network traffic on a named _i_n_t_e_r_f_a_c_e, or on the first interface it can find which looks like an external interface if none is specified, and displays a table of current bandwidth usage by pairs of hosts. iiffttoopp must be run with sufficient permissions to monitor all network traffic on the _i_n_t_e_r_f_a_c_e; see ppccaapp(3) for more information, but on most systems this means that it must be run as root. By default, iiffttoopp will look up the hostnames associated with addresses it finds in packets. This can cause substantial traffic of itself, and may result in a confusing display. You may wish to suppress display of DNS traffic by using filter code such as nnoott ppoorrtt ddoommaaiinn, or switch it off entirely, by using the --nn option or by pressing rr when the program is running. By default, iiffttoopp counts all IP packets that pass through the filter, and the direction of the packet is determined according to the direc- tion the packet is moving across the interface. Using the --FF option it is possible to get iiffttoopp to show packets entering and leaving a given network. For example, iiffttoopp --FF 1100..00..00..00//225555..00..00..00 will analyse packets flowing in and out of the 10.* network. Some other filter ideas: nnoott eetthheerr hhoosstt ffff::ffff::ffff::ffff::ffff::ffff Ignore ethernet broadcast packets. ppoorrtt hhttttpp aanndd nnoott hhoosstt _w_e_b_c_a_c_h_e_._e_x_a_m_p_l_e_._c_o_m Count web traffic only, unless it is being directed through a local web cache. iiccmmpp How much bandwidth are users wasting trying to figure out why the network is slow? OOPPTTIIOONNSS --hh Print a summary of usage. --nn Don't do hostname lookups. --NN Do not resolve port number to service names --pp Run in promiscuous mode, so that traffic which does not pass directly through the specified interface is also counted. --PP Turn on port display. --ll Display and count datagrams addressed to or from link-local IPv6 addresses. The default is not to display that address category. --bb Don't display bar graphs of traffic. --mm _l_i_m_i_t Set the upper limit for the bandwidth scale. Specified as a number with a 'K', 'M' or 'G' suffix. --BB Display bandwidth rates in bytes/sec rather than bits/sec. --ii _i_n_t_e_r_f_a_c_e Listen to packets on _i_n_t_e_r_f_a_c_e. --ff _f_i_l_t_e_r _c_o_d_e Use _f_i_l_t_e_r _c_o_d_e to select the packets to count. Only IP packets are ever counted, so the specified code is evaluated as ((_f_i_l_t_e_r _c_o_d_e)) aanndd iipp. --FF _n_e_t/_m_a_s_k 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 _m_a_s_k 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. --GG _n_e_t_6/_m_a_s_k_6 Specifies an IPv6 network for traffic analysis. The value of _m_a_s_k_6 can be given as a prefix length or as a numerical address string for more compound bitmasking. --cc _c_o_n_f_i_g _f_i_l_e Specifies an alternate config file. If not specified, iftop will use ~~//..iiffttoopprrcc if it exists. See below for a description of config files --tt _t_e_x_t _o_u_t_p_u_t _m_o_d_e Use text interface without ncurses and print the output to STD- OUT. DDIISSPPLLAAYY When running, iiffttoopp uses the whole screen to display network usage. At the top of the display is a logarithmic scale for the bar graph which gives a visual indication of traffic. The main part of the display lists, for each pair of hosts, the rate at which data has been sent and received over the preceding 2, 10 and 40 second intervals. The direction of data flow is indicated by arrows, <= and =>. For instance, foo.example.com => bar.example.com 1Kb 500b 100b <= 2Mb 2Mb 2Mb shows, on the first line, traffic from ffoooo..eexxaammppllee..ccoomm to bbaarr..eexxaamm-- ppllee..ccoomm; in the preceding 2 seconds, this averaged 1Kbit/s, around half that amount over the preceding 10s, and a fifth of that over the whole of the last 40s. During each of those intervals, the data sent in the other direction was about 2Mbit/s. On the actual display, part of each line is inverted to give a visual indication of the 10s average of traffic. You might expect to see something like this where host ffoooo is making repeated HTTP requests to bbaarr, which is sending data back which saturates a 2Mbit/s link. By default, the pairs of hosts responsible for the most traffic (10 second average) are displayed at the top of the list. At the bottom of the display, various totals are shown, including peak traffic over the last 40s, total traffic transferred (after filtering), and total transfer rates averaged over 2s, 10s and 40s. SSOOUURRCCEE // DDEESSTT AAGGGGRREEGGAATTIIOONN By pressing ss or dd while iiffttoopp is running, all traffic for each source or destination will be aggregated together. This is most useful when iiffttoopp is run in promiscuous mode, or is run on a gateway machine. PPOORRTT DDIISSPPLLAAYY SS or DD toggle the display of source and destination ports respectively. pp will toggle port display on/off. DDIISSPPLLAAYY TTYYPPEE tt cycles through the four line display modes; the default 2-line dis- play, with sent and received traffic on separate lines, and 3 1-line displays, with sent, received, or total traffic shown. DDIISSPPLLAAYY OORRDDEERR By default, the display is ordered according to the 10s average (2nd column). By pressing 11, 22 or 33 it is possible to sort by the 1st, 2nd or 3rd column. By pressing << or >> the display will be sorted by source or destination hostname respectively. DDIISSPPLLAAYY FFIILLTTEERRIINNGG ll allows you to enter a POSIX extended regular expression that will be used to filter hostnames shown in the display. This is a good way to quickly limit what is shown on the display. Note that this happens at a much later stage than filter code, and does not affect what is actu- ally captured. Display filters DO NOT affect the totals at the bottom of the screen. PPAAUUSSEE DDIISSPPLLAAYY // FFRREEEEZZEE OORRDDEERR PP will pause the current display. oo will freeze the current screen order. This has the side effect that traffic between hosts not shown on the screen at the time will not be shown at all, although it will be included in the totals at the bottom of the screen. SSCCRROOLLLL DDIISSPPLLAAYY jj and kk will scroll the display of hosts. This feature is most useful when the display order is frozen (see above). FFIILLTTEERR CCOODDEE ff allows you to edit the filter code whilst iftop running. This can lead to some unexpected behaviour. CCOONNFFIIGG FFIILLEE iftop can read its configuration from a config file. If the --cc option is not specified, iftop will attempt to read its configuration from ~~//..iiffttoopprrcc, if it exists. Any command line options specified will override settings in the config file. The config file consists of one configuration directive per line. Each directive is a name value pair, for example: interface: eth0 sets the network interface. The following config directives are sup- ported: iinntteerrffaaccee:: _i_f Sets the network interface to _i_f. ddnnss--rreessoolluuttiioonn:: _(_y_e_s_|_n_o_) Controls reverse lookup of IP addresses. ppoorrtt--rreessoolluuttiioonn:: _(_y_e_s_|_n_o_) Controls conversion of port numbers to service names. ffiilltteerr--ccooddee:: _b_p_f Sets the filter code to _b_p_f. sshhooww--bbaarrss:: _(_y_e_s_|_n_o_) Controls display of bar graphs. pprroommiissccuuoouuss:: _(_y_e_s_|_n_o_) Puts the interface into promiscuous mode. ppoorrtt--ddiissppllaayy:: _(_o_f_f_|_s_o_u_r_c_e_-_o_n_l_y_|_d_e_s_t_i_n_a_t_i_o_n_-_o_n_l_y_|_o_n_) Controls display of port numbers. lliinnkk--llooccaall:: _(_y_e_s_|_n_o_) Determines displaying of link-local IPv6 addresses. hhiiddee--ssoouurrccee:: _(_y_e_s_|_n_o_) Hides source host names. hhiiddee--ddeessttiinnaattiioonn:: _(_y_e_s_|_n_o_) Hides destination host names. uussee--bbyytteess:: _(_y_e_s_|_n_o_) Use bytes for bandwidth display, rather than bits. ssoorrtt:: _(_2_s_|_1_0_s_|_4_0_s_|_s_o_u_r_c_e_|_d_e_s_t_i_n_a_t_i_o_n_) Sets which column is used to sort the display. lliinnee--ddiissppllaayy:: _(_t_w_o_-_l_i_n_e_|_o_n_e_-_l_i_n_e_-_b_o_t_h_|_o_n_e_-_l_i_n_e_-_s_e_n_t_|_o_n_e_-_l_i_n_e_-_r_e_c_e_i_v_e_d_) Controls the appearance of each item in the display. sshhooww--ttoottaallss:: _(_y_e_s_|_n_o_) Shows cumulative total for each item. lloogg--ssccaallee:: _(_y_e_s_|_n_o_) Use a logarithmic scale for bar graphs. mmaaxx--bbaannddwwiiddtthh:: _b_w Fixes the maximum for the bar graph scale to _b_w, e.g. "10M". Note that the value has to always be in bits, regardless if the option to display in bytes has been chosen. nneett--ffiilltteerr:: _n_e_t_/_m_a_s_k Defines an IP network boundary for determining packet direction. nneett--ffiilltteerr66:: _n_e_t_6_/_m_a_s_k_6 Defines an IPv6 network boundary for determining packet direc- tion. ssccrreeeenn--ffiilltteerr:: _r_e_g_e_x_p Sets a regular expression to filter screen output. QQUUIIRRKKSS ((aakkaa tthheeyy''rree ffeeaattuurreess,, nnoott bbuuggss)) There are some circumstances in which iftop may not do what you expect. In most cases what it is doing is logical, and we believe it is correct behaviour, although I'm happy to hear reasoned arguments for alterna- tive behaviour. TToottaallss ddoonn''tt aadddd uupp There are several reasons why the totals may not appear to add up. The most obvious is having a screen filter in effect, or screen ordering frozen. In this case some captured information is not being shown to you, but is included in the totals. A more subtle explanation comes about when running in promiscuous mode without specifying a --FF option. In this case there is no easy way to assign the direction of traffic between two third parties. For the purposes of the main display this is done in an arbitrary fashion (by ordering of IP addresses), but for the sake of totals all traffic between other hosts is accounted as incoming, because that's what it is from the point of view of your interface. The --FF option allows you to specify an arbitrary network boundary, and to show traffic flowing across it. PPeeaakk ttoottaallss ddoonn''tt aadddd uupp Again, this is a feature. The peak sent and peak received didn't nec- essarily happen at the same time. The peak total is the maximum of sent plus received in each captured time division. CChhaannggiinngg tthhee ffiilltteerr ccooddee ddooeessnn''tt sseeeemm ttoo wwoorrkk Give it time. Changing the filter code affects what is captured from the time that you entered it, but most of what is on the display is based on some fraction of the last 40s window of capturing. After changing the filter there may be entries on the display that are disal- lowed by the current filter for up to 40s. DISPLAY FILTERING has imme- diate effect and does not affect what is captured. FFIILLEESS ~~//..iiffttoopprrcc Configuration file for iftop. SSEEEE AALLSSOO ttccppdduummpp(8), ppccaapp(3), ddrriiffttnneett(1). AAUUTTHHOORR Paul Warren <pdw@ex-parrot.com> VVEERRSSIIOONN $Id: iftop.cat,v 1.1.1.2 2016/10/18 14:04:50 misho Exp $ CCOOPPYYIINNGG This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MER- CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. (nlu+10 IFTOP(8)