20 ukazov Netstat za upravljanje omrežja Linux
netstat (omrežna statistika) je orodje ukazne vrstice za spremljanje omrežnih povezav tako dohodnih kot odhodnih, kot tudi ogled usmerjevalnih tabel, statistike vmesnikov itd.
netstat je na voljo v vseh operacijskih sistemih, podobnih Unixu, na voljo pa je tudi v operacijskem sistemu Windows. Zelo je uporaben v smislu odpravljanja težav v omrežju in merjenja učinkovitosti. netstat je eno najosnovnejših orodij za odpravljanje napak omrežnih storitev, ki vam pove, katera vrata so odprta in ali kateri program posluša na vratih.
To orodje je zelo pomembno in zelo koristno za skrbnike omrežja Linux in sistemske skrbnike za spremljanje in odpravljanje težav, povezanih z omrežjem, in za določanje učinkovitosti omrežnega prometa. Ta članek prikazuje uporabo ukaza netstat s primeri, ki so lahko koristni pri vsakodnevnem delovanju.
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Seznam vseh vrat (tako TCP kot UDP) z uporabo možnosti netstat -a.
# netstat -a | more Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:sunrpc *:* LISTEN tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT tcp 0 0 localhost:smtp *:* LISTEN tcp 0 0 *:59482 *:* LISTEN udp 0 0 *:35036 *:* udp 0 0 *:npmp-local *:* Active UNIX domain sockets (servers and established) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 16972 /tmp/orbit-root/linc-76b-0-6fa08790553d6 unix 2 [ ACC ] STREAM LISTENING 17149 /tmp/orbit-root/linc-794-0-7058d584166d2 unix 2 [ ACC ] STREAM LISTENING 17161 /tmp/orbit-root/linc-792-0-546fe905321cc unix 2 [ ACC ] STREAM LISTENING 15938 /tmp/orbit-root/linc-74b-0-415135cb6aeab
Navedite samo povezave vrat TCP (Transmission Control Protocol) s pomočjo netstat -at.
# netstat -at Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:ssh *:* LISTEN tcp 0 0 localhost:ipp *:* LISTEN tcp 0 0 localhost:smtp *:* LISTEN tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT
Navedite samo povezave vrat UDP (User Datagram Protocol) z uporabo netstat -au.
# netstat -au Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State udp 0 0 *:35036 *:* udp 0 0 *:npmp-local *:* udp 0 0 *:mdns *:*
Navedba vseh povezav aktivnih vrat poslušanja z netstat -l.
# netstat -l Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:58642 *:* LISTEN tcp 0 0 *:ssh *:* LISTEN udp 0 0 *:35036 *:* udp 0 0 *:npmp-local *:* Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 16972 /tmp/orbit-root/linc-76b-0-6fa08790553d6 unix 2 [ ACC ] STREAM LISTENING 17149 /tmp/orbit-root/linc-794-0-7058d584166d2 unix 2 [ ACC ] STREAM LISTENING 17161 /tmp/orbit-root/linc-792-0-546fe905321cc unix 2 [ ACC ] STREAM LISTENING 15938 /tmp/orbit-root/linc-74b-0-415135cb6aeab
Seznam vseh aktivnih vrat TCP za poslušanje z uporabo možnosti netstat -lt.
# netstat -lt Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:dctp *:* LISTEN tcp 0 0 *:mysql *:* LISTEN tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:munin *:* LISTEN tcp 0 0 *:ftp *:* LISTEN tcp 0 0 localhost.localdomain:ipp *:* LISTEN tcp 0 0 localhost.localdomain:smtp *:* LISTEN tcp 0 0 *:http *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 *:https *:* LISTEN
Seznam vseh aktivnih vrat UDP, ki poslušajo, z uporabo možnosti netstat -lu.
# netstat -lu Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State udp 0 0 *:39578 *:* udp 0 0 *:meregister *:* udp 0 0 *:vpps-qua *:* udp 0 0 *:openvpn *:* udp 0 0 *:mdns *:* udp 0 0 *:sunrpc *:* udp 0 0 *:ipp *:* udp 0 0 *:60222 *:* udp 0 0 *:mdns *:*
Seznam vseh aktivnih vrat poslušanja UNIX z uporabo netstat -lx.
# netstat -lx Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 4171 @ISCSIADM_ABSTRACT_NAMESPACE unix 2 [ ACC ] STREAM LISTENING 5767 /var/run/cups/cups.sock unix 2 [ ACC ] STREAM LISTENING 7082 @/tmp/fam-root- unix 2 [ ACC ] STREAM LISTENING 6157 /dev/gpmctl unix 2 [ ACC ] STREAM LISTENING 6215 @/var/run/hald/dbus-IcefTIUkHm unix 2 [ ACC ] STREAM LISTENING 6038 /tmp/.font-unix/fs7100 unix 2 [ ACC ] STREAM LISTENING 6175 /var/run/avahi-daemon/socket unix 2 [ ACC ] STREAM LISTENING 4157 @ISCSID_UIP_ABSTRACT_NAMESPACE unix 2 [ ACC ] STREAM LISTENING 60835836 /var/lib/mysql/mysql.sock unix 2 [ ACC ] STREAM LISTENING 4645 /var/run/audispd_events unix 2 [ ACC ] STREAM LISTENING 5136 /var/run/dbus/system_bus_socket unix 2 [ ACC ] STREAM LISTENING 6216 @/var/run/hald/dbus-wsUBI30V2I unix 2 [ ACC ] STREAM LISTENING 5517 /var/run/acpid.socket unix 2 [ ACC ] STREAM LISTENING 5531 /var/run/pcscd.comm
Prikaže statistiko po protokolu. Privzeto so prikazani statistični podatki za protokole TCP, UDP, ICMP in IP. S parametrom -s lahko določite nabor protokolov.
# netstat -s Ip: 2461 total packets received 0 forwarded 0 incoming packets discarded 2431 incoming packets delivered 2049 requests sent out Icmp: 0 ICMP messages received 0 input ICMP message failed. ICMP input histogram: 1 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 1 Tcp: 159 active connections openings 1 passive connection openings 4 failed connection attempts 0 connection resets received 1 connections established 2191 segments received 1745 segments send out 24 segments retransmited 0 bad segments received. 4 resets sent Udp: 243 packets received 1 packets to unknown port received. 0 packet receive errors 281 packets sent
Prikaz statistike samo protokola TCP z uporabo možnosti netstat -st.
# netstat -st Tcp: 2805201 active connections openings 1597466 passive connection openings 1522484 failed connection attempts 37806 connection resets received 1 connections established 57718706 segments received 64280042 segments send out 3135688 segments retransmited 74 bad segments received. 17580 resets sent
# netstat -su Udp: 1774823 packets received 901848 packets to unknown port received. 0 packet receive errors 2968722 packets sent
Če se prikaže ime storitve z njihovo številko PID, bo z možnostjo netstat -tp prikazano “PID/Ime programa”.
# netstat -tp Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED 2179/sshd tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT 1939/clock-applet
Prikaže se način Promiscuous s stikalom -ac, netstat natisne izbrane informacije ali osveži zaslon vsakih pet sekund. Privzeta osvežitev zaslona v vsaki sekundi.
# netstat -ac 5 | grep tcp tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:58642 *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 localhost:ipp *:* LISTEN tcp 0 0 localhost:smtp *:* LISTEN tcp 1 0 192.168.0.2:59447 www.gov.com:http CLOSE_WAIT tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 localhost:ipp *:* LISTEN tcp 0 0 localhost:smtp *:* LISTEN tcp 0 0 *:59482 *:* LISTEN
Prikažite usmerjevalno tabelo jedra IP z ukazom netstat in route.
# netstat -r Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 192.168.0.0 * 255.255.255.0 U 0 0 0 eth0 link-local * 255.255.0.0 U 0 0 0 eth0 default 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
Prikaz paketnih transakcij omrežnega vmesnika, vključno s prenosom in sprejemanjem paketov z velikostjo MTU.
# netstat -i Kernel Interface table Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1500 0 4459 0 0 0 4057 0 0 0 BMRU lo 16436 0 8 0 0 0 8 0 0 0 LRU
Prikaz tabele vmesnika jedra, podobno kot ukaz ifconfig.
# netstat -ie Kernel Interface table eth0 Link encap:Ethernet HWaddr 00:0C:29:B4:DA:21 inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb4:da21/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:4486 errors:0 dropped:0 overruns:0 frame:0 TX packets:4077 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2720253 (2.5 MiB) TX bytes:1161745 (1.1 MiB) Interrupt:18 Base address:0x2000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:480 (480.0 b) TX bytes:480 (480.0 b)
Prikaže informacije o članstvu v multicast skupini za IPv4 in IPv6.
# netstat -g IPv6/IPv4 Group Memberships Interface RefCnt Group --------------- ------ --------------------- lo 1 all-systems.mcast.net eth0 1 224.0.0.251 eth0 1 all-systems.mcast.net lo 1 ff02::1 eth0 1 ff02::202 eth0 1 ff02::1:ffb4:da21 eth0 1 ff02::1
Če želite informacije o Netstatu dobiti vsakih nekaj sekund, uporabite naslednji ukaz, ki bo neprekinjeno tiskal podatke o Netstatu, recimo vsakih nekaj sekund.
# netstat -c Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:36944 TIME_WAIT tcp 0 0 linux-console.net:http sg2nlhg010.shr.prod.s:42110 TIME_WAIT tcp 0 132 linux-console.net:ssh 115.113.134.3.static-:64662 ESTABLISHED tcp 0 0 linux-console.net:http crawl-66-249-71-240.g:41166 TIME_WAIT tcp 0 0 localhost.localdomain:54823 localhost.localdomain:smtp TIME_WAIT tcp 0 0 localhost.localdomain:54822 localhost.localdomain:smtp TIME_WAIT tcp 0 0 linux-console.net:http sg2nlhg010.shr.prod.s:42091 TIME_WAIT tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:36998 TIME_WAIT
Iskanje nekonfiguriranih družin naslovov z nekaj koristnimi informacijami.
# netstat --verbose netstat: no support for `AF IPX' on this system. netstat: no support for `AF AX25' on this system. netstat: no support for `AF X25' on this system. netstat: no support for `AF NETROM' on this system.
Ugotovite, koliko programov za poslušanje se izvaja na vratih.
# netstat -ap | grep http tcp 0 0 *:http *:* LISTEN 9056/httpd tcp 0 0 *:https *:* LISTEN 9056/httpd tcp 0 0 linux-console.net:http sg2nlhg008.shr.prod.s:35248 TIME_WAIT - tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:57783 TIME_WAIT - tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:57769 TIME_WAIT - tcp 0 0 linux-console.net:http sg2nlhg008.shr.prod.s:35270 TIME_WAIT - tcp 0 0 linux-console.net:http sg2nlhg009.shr.prod.s:41637 TIME_WAIT - tcp 0 0 linux-console.net:http sg2nlhg009.shr.prod.s:41614 TIME_WAIT - unix 2 [ ] STREAM CONNECTED 88586726 10394/httpd
# netstat --statistics --raw Ip: 62175683 total packets received 52970 with invalid addresses 0 forwarded Icmp: 875519 ICMP messages received destination unreachable: 901671 echo request: 8 echo replies: 16253 IcmpMsg: InType0: 83 IpExt: InMcastPkts: 117
To je to. Če iščete več informacij in možnosti o ukazu netstat, glejte priročnik za netstat priročnik ali uporabite ukaz man netstat, če želite vedeti vse informacije. Če smo na seznamu kaj zamudili, nas obvestite v spodnjem oddelku za komentarje. Torej bi lahko ta seznam še naprej posodabljali na podlagi vaših komentarjev.