22 Linux iwu ịkparịta ụka n'Ịntanet maka Sysadmin
Ọrụ onye na-ahụ maka sistemụ na-arụ oge niile gụnyere ịhazi, idowe, nchọpụta nsogbu, na ijikwa sava na netwọkụ n'ime ebe data. Enwere ọtụtụ ngwaọrụ na akụrụngwa na Linux emebere maka ebumnuche nhazi.
N'edemede a, anyị ga-enyocha ụfọdụ ngwaọrụ na akụrụngwa iwu na-ejikarị maka njikwa netwọkụ na Linux, n'okpuru ụdị dị iche iche. Anyị ga-akọwa ụfọdụ ihe atụ eji eme ihe, nke ga-eme ka njikwa netwọkụ dịkwuo mfe na Linux.
Na ibe a
- ifconfig Iwu
- ip Iwu
- iwu ifup
- ethtool Iwu
- Ping Command
- iwu traceroute
- mtr Iwu
- iwu ụzọ
- nmcli Iwu
- iwu netstat
- ss Iwu
- nc Iwu
- nmap Iwu
- iwu onye ọbịa
- gwuo Iwu
- nslookup Command
- tcpdump Iwu
- Wireshark Utility
- Ngwaọrụ bmon
- Firewall iptables
- Firewalld
- UFW Firewall
- Nduzi bara uru maka Nmap (Nchọpụta nchekwa netwọkụ) na Kali Linux
- Chọta adreesị IP niile ndị ọbịa dị ndụ ejikọrọ na netwọkụ na Linux
- Nduzi bụ isi na IPTables (Linux Firewall) Ndụmọdụ/Iwu
- 25 Iwu IPtable Firewall bara uru Onye nchịkwa Linux ọ bụla kwesịrị ịma
- Otu esi edobe ọkụ Iptables iji mee ka ịnweta ọrụ dị anya
- Etu esi egbochi arịrịọ ICMP Ping na sistemụ Linux
- Iwu ‘FirewallD’ bara uru iji hazie na jikwaa firewall na Linux Otu esi ahazi 'FirewallD' na RHEL/CentOS 7 na Fedora 21
- Otu esi amalite/Kwụsị na Kwado/gbanyụọ FirewallD na Iptables Firewall na Linux
- Ịtọlite Samba wee hazie FirewallD na SELinux iji kwe ka ikesa faịlụ na Linux/Windows
Ndepụta a bakwara uru nye ndị injinia netwọkụ Linux oge niile.
Nhazi netwọkụ, nchọpụta nsogbu na ngwa nbipu
ifconfig bụ ngwá ọrụ ntanetịime iwu-ahịrị maka nhazi nhazi netwọkụ ma a na-ejikwa ya ịmalite oghere na oge buut usoro. Ozugbo ihe nkesa na-arụ ọrụ, enwere ike iji ya kenye Adreesị IP na interface ma mee ka ma ọ bụ gbanyụọ interface ahụ na-achọ.
A na-ejikwa ya ele Adreesị IP, adreesị ngwaike/MAC, yana MTU (Njedebe Nnyefe Kachasị) nke oghere ndị na-arụ ọrụ ugbu a. Ifconfig bara uru maka nbipu ma ọ bụ ịrụ ọrụ nhazi usoro.
Nke a bụ ọmụmaatụ iji gosipụta ọkwa nke interface netwọk niile na-arụ ọrụ.
$ ifconfig
enp1s0 Link encap:Ethernet HWaddr 28:d2:44:eb:bd:98
inet addr:192.168.0.103 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::8f0c:7825:8057:5eec/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:169854 errors:0 dropped:0 overruns:0 frame:0
TX packets:125995 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:174146270 (174.1 MB) TX bytes:21062129 (21.0 MB)
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:65536 Metric:1
RX packets:15793 errors:0 dropped:0 overruns:0 frame:0
TX packets:15793 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:2898946 (2.8 MB) TX bytes:2898946 (2.8 MB)
Iji depụta ihu ihu niile dị ugbu a, ma elu ma ọ bụ ala, jiri ọkọlọtọ -a.
$ ifconfig -a
Iji kenye adreesị IP na interface, jiri iwu na-esonụ.
$ sudo ifconfig eth0 192.168.56.5 netmask 255.255.255.0
Iji mee ka interface netwọk rụọ ọrụ, pịnye.
$ sudo ifconfig up eth0
Iji gbanyụọ ma ọ bụ mechie interface netwọk, pịnye.
$ sudo ifconfig down eth0
Rịba ama: Ọ bụ ezie na ifconfig bụ ngwá ọrụ dị ukwuu, ọ bụzi ihe na-abaghị uru (nke a kwụsịrị), onye na-anọchi ya bụ iwu ip nke a kọwara n'okpuru ebe a.
Kedu ihe dị iche n'etiti ifconfig na iwu ip iji mụtakwuo banyere ya.)
Iwu na-esonụ ga-egosi adreesị IP na ozi ndị ọzọ gbasara interface netwọk.
$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 28:d2:44:eb:bd:98 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.103/24 brd 192.168.0.255 scope global dynamic enp1s0
valid_lft 5772sec preferred_lft 5772sec
inet6 fe80::8f0c:7825:8057:5eec/64 scope link
valid_lft forever preferred_lft forever
3: wlp2s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 38:b1:db:7c:78:c7 brd ff:ff:ff:ff:ff:ff
...
Iji kenye Adreesị IP nwa oge na ntanetịime netwọkụ akọwapụtara (eth0), pịnye.
$ sudo ip addr add 192.168.56.1 dev eth0
Iji wepu adreesị IP ekenyere na interface netwọk (eth0), pịnye.
$ sudo ip addr del 192.168.56.15/24 dev eth0
Iji gosi tebụl agbataobi dị ugbu a na kernel, pịnye.
$ ip neigh 192.168.0.1 dev enp1s0 lladdr 10:fe:ed:3d:f3:82 REACHABLE
iwu ifup na-arụ ọrụ interface netwọk, na-eme ka ọ dị maka ịnyefe na ịnata data.
$ sudo ifup eth0
iwu ifdown na-ewepu interface netwọk, idobe ya na ọnọdụ ebe ọ nweghị ike ịnyefe ma ọ bụ nata data.
$ sudo ifdown eth0
iwu ifquery na-eji enyocha nhazi interface netwọk, na-enye gị ohere ịnweta azịza ajụjụ gbasara otu esi ahazi ya ugbu a.
$ sudo ifquery eth0
ethtool bụ akụrụngwa iwu maka ịza ajụjụ na imegharị paramita njikwa ihe njikwa netwọkụ yana ndị ọkwọ ụgbọ ala ngwaọrụ. Ọmụmaatụ dị n'okpuru na-egosi ojiji nke ethtool yana iwu ka ịlele paramita maka interface netwọkụ.
$ sudo ethtool enp0s3 Settings for enp0s3: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: on MDI-X: off (auto) Supports Wake-on: umbg Wake-on: d Current message level: 0x00000007 (7) drv probe link Link detected: yes
ping (Packet INternet Groper) bụ akụrụngwa a na-ejikarị maka ịnwale njikọta n'etiti sistemụ abụọ na netwọkụ (Local Area Network (LAN) ma ọ bụ Wide Area Network (WAN)). Ọ na-eji ICMP (Internet Control Message Protocol) na-ekwurịta okwu na ọnụ na netwọk.
Iji nwalee njikọta na ọnụ ụzọ ọzọ, nye naanị IP ma ọ bụ aha nnabata ya, dịka ọmụmaatụ.
$ ping 192.168.0.103 PING 192.168.0.103 (192.168.0.103) 56(84) bytes of data. 64 bytes from 192.168.0.103: icmp_seq=1 ttl=64 time=0.191 ms 64 bytes from 192.168.0.103: icmp_seq=2 ttl=64 time=0.156 ms 64 bytes from 192.168.0.103: icmp_seq=3 ttl=64 time=0.179 ms 64 bytes from 192.168.0.103: icmp_seq=4 ttl=64 time=0.182 ms 64 bytes from 192.168.0.103: icmp_seq=5 ttl=64 time=0.207 ms 64 bytes from 192.168.0.103: icmp_seq=6 ttl=64 time=0.157 ms ^C --- 192.168.0.103 ping statistics --- 6 packets transmitted, 6 received, 0% packet loss, time 5099ms rtt min/avg/max/mdev = 0.156/0.178/0.207/0.023 ms
Ị nwekwara ike ịgwa ping ka ọ pụọ mgbe ọnụọgụ ECHO_REQUEST akọwapụtara, na-eji ọkọlọtọ -c dịka egosiri.
$ ping -c 4 192.168.0.103 PING 192.168.0.103 (192.168.0.103) 56(84) bytes of data. 64 bytes from 192.168.0.103: icmp_seq=1 ttl=64 time=1.09 ms 64 bytes from 192.168.0.103: icmp_seq=2 ttl=64 time=0.157 ms 64 bytes from 192.168.0.103: icmp_seq=3 ttl=64 time=0.163 ms 64 bytes from 192.168.0.103: icmp_seq=4 ttl=64 time=0.190 ms --- 192.168.0.103 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 3029ms rtt min/avg/max/mdev = 0.157/0.402/1.098/0.402 ms
Traceroute bụ akụrụngwa na-enye iwu maka ịchọta ụzọ zuru oke site na sistemụ mpaghara gị gaa na sistemụ netwọkụ ọzọ. Ọ na-ebipụta ọtụtụ hops (Router IPs) n'ụzọ ahụ ị na-eme njem iji ruo ihe nkesa njedebe. Ọ bụ ngwa nchọpụta nsogbu netwọk dị mfe iji mgbe iwu ping gasịrị.
N'ihe atụ a, anyị na-enyocha ngwugwu ụzọ na-esi na sistemụ mpaghara gaa na otu n'ime sava Google nwere adreesị IP 216.58.204.46.
$ traceroute 216.58.204.46 traceroute to 216.58.204.46 (216.58.204.46), 30 hops max, 60 byte packets 1 gateway (192.168.0.1) 0.487 ms 0.277 ms 0.269 ms 2 5.5.5.215 (5.5.5.215) 1.846 ms 1.631 ms 1.553 ms 3 * * * 4 72.14.194.226 (72.14.194.226) 3.762 ms 3.683 ms 3.577 ms 5 108.170.248.179 (108.170.248.179) 4.666 ms 108.170.248.162 (108.170.248.162) 4.869 ms 108.170.248.194 (108.170.248.194) 4.245 ms 6 72.14.235.133 (72.14.235.133) 72.443 ms 209.85.241.175 (209.85.241.175) 62.738 ms 72.14.235.133 (72.14.235.133) 65.809 ms 7 66.249.94.140 (66.249.94.140) 128.726 ms 127.506 ms 209.85.248.5 (209.85.248.5) 127.330 ms 8 74.125.251.181 (74.125.251.181) 127.219 ms 108.170.236.124 (108.170.236.124) 212.544 ms 74.125.251.181 (74.125.251.181) 127.249 ms 9 216.239.49.134 (216.239.49.134) 236.906 ms 209.85.242.80 (209.85.242.80) 254.810 ms 254.735 ms 10 209.85.251.138 (209.85.251.138) 252.002 ms 216.239.43.227 (216.239.43.227) 251.975 ms 209.85.242.80 (209.85.242.80) 236.343 ms 11 216.239.43.227 (216.239.43.227) 251.452 ms 72.14.234.8 (72.14.234.8) 279.650 ms 277.492 ms 12 209.85.250.9 (209.85.250.9) 274.521 ms 274.450 ms 209.85.253.249 (209.85.253.249) 270.558 ms 13 209.85.250.9 (209.85.250.9) 269.147 ms 209.85.254.244 (209.85.254.244) 347.046 ms 209.85.250.9 (209.85.250.9) 285.265 ms 14 64.233.175.112 (64.233.175.112) 344.852 ms 216.239.57.236 (216.239.57.236) 343.786 ms 64.233.175.112 (64.233.175.112) 345.273 ms 15 108.170.246.129 (108.170.246.129) 345.054 ms 345.342 ms 64.233.175.112 (64.233.175.112) 343.706 ms 16 108.170.238.119 (108.170.238.119) 345.610 ms 108.170.246.161 (108.170.246.161) 344.726 ms 108.170.238.117 (108.170.238.117) 345.536 ms 17 lhr25s12-in-f46.1e100.net (216.58.204.46) 345.382 ms 345.031 ms 344.884 ms
MTR bụ ngwaọrụ nyocha netwọkụ iwu ọgbara ọhụrụ nke jikọtara ọrụ ping na traceroute n'ime otu ngwaọrụ nyocha. A na-emelite mmepụta ya ozugbo, na ndabara ruo mgbe ị ga-apụ na mmemme site na ịpị q.
Ụzọ kachasị mfe iji na-agba ọsọ mtr bụ ịnye ya aha nnabata ma ọ bụ adreesị IP dịka arụmụka, dị ka ndị a.
$ mtr google.com OR $ mtr 216.58.223.78
linux-console.net (0.0.0.0) Thu Jul 12 08:58:27 2018 First TTL: 1 Host Loss% Snt Last Avg Best Wrst StDev 1. 192.168.0.1 0.0% 41 0.5 0.6 0.4 1.7 0.2 2. 5.5.5.215 0.0% 40 1.9 1.5 0.8 7.3 1.0 3. 209.snat-111-91-120.hns.net.in 23.1% 40 1.9 2.7 1.7 10.5 1.6 4. 72.14.194.226 0.0% 40 89.1 5.2 2.2 89.1 13.7 5. 108.170.248.193 0.0% 40 3.0 4.1 2.4 52.4 7.8 6. 108.170.237.43 0.0% 40 2.9 5.3 2.5 94.1 14.4 7. bom07s10-in-f174.1e100.net 0.0% 40 2.6 6.7 2.3 79.7 16.
Ị nwere ike belata ọnụ ọgụgụ pings na otu uru wee pụọ mtr mgbe pings ndị ahụ gasịrị, na-eji -c ọkọlọtọ dị ka egosiri.
$ mtr -c 4 google.com
Ụzọ ahụ bụ ihe eji enyere ndụ aka maka igosipụta ma ọ bụ ijikwa tebụl ntụgharị IP nke sistemụ Linux. A na-ejikarị ya hazie ụzọ kwụ ọtọ gaa na ndị ọbịa ma ọ bụ netwọkụ akọwapụtara site na interface.
Ị nwere ike ịlele tebụl ntụgharị kernel IP site na ịpị.
$ route Destination Gateway Genmask Flags Metric Ref Use Iface default gateway 0.0.0.0 UG 100 0 0 enp0s3 192.168.0.0 0.0.0.0 255.255.255.0 U 100 0 0 enp0s3 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
Enwere ọtụtụ iwu ị nwere ike iji hazie ntụgharị. Nke a bụ ụfọdụ ndị bara uru:
Tinye ụzọ ámá ndabara na tebụl ntụgharị.
$ sudo route add default gw <gateway-ip>
Tinye ụzọ netwọkụ na tebụl ntụgharị.
$ sudo route add -net <network ip/cidr> gw <gateway ip> <interface>
Hichapụ otu ntinye ụzọ n'ime tebụl ntụgharị.
$ sudo route del -net <network ip/cidr>
Nmcli bụ ngwa dị mfe iji, ngwa ahịrị iwu ederede iji kọọ ọkwa netwọkụ, jikwaa njikọ netwọkụ, yana jikwaa NetworkManager.
Ka ilele ngwaọrụ netwọkụ gị niile, pịnye.
$ nmcli dev status DEVICE TYPE STATE CONNECTION virbr0 bridge connected virbr0 enp0s3 ethernet connected Wired connection 1
Ka ịlele njikọ netwọkụ na sistemụ gị, pịnye.
$ nmcli con show Wired connection 1 bc3638ff-205a-3bbb-8845-5a4b0f7eef91 802-3-ethernet enp0s3 virbr0 00f5d53e-fd51-41d3-b069-bdfd2dde062b bridge virbr0
Ka ịhụ naanị njikọ ndị nọ n'ọrụ, tinye ọkọlọtọ -a.
$ nmcli con show -a
Ngwaọrụ nyocha na arụmọrụ netwọkụ
netstat bụ ngwa ahịrị iwu na-egosiputa ozi bara uru dị ka njikọ netwọkụ, tebụl ntụgharị, ọnụ ọgụgụ interface, na ọtụtụ ndị ọzọ, gbasara sistemụ netwọkụ Linux. Ọ bara uru maka nchọpụta nsogbu netwọkụ na nyocha arụmọrụ.
Na mgbakwunye, ọ bụkwa ngwa nbibi ọrụ netwọkụ bụ isi eji elele mmemme na-ege ntị na ọdụ ụgbọ mmiri. Dịka ọmụmaatụ, iwu na-esote ga-egosi ọdụ ụgbọ mmiri TCP niile na ọnọdụ ịge ntị yana mmemme na-ege ntị na ha.
$ sudo netstat -tnlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 1257/master tcp 0 0 127.0.0.1:5003 0.0.0.0:* LISTEN 1/systemd tcp 0 0 0.0.0.0:110 0.0.0.0:* LISTEN 1015/dovecot tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 1015/dovecot tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemd tcp 0 0 0.0.0.0:465 0.0.0.0:* LISTEN 1257/master tcp 0 0 0.0.0.0:53 0.0.0.0:* LISTEN 1404/pdns_server tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 1064/pure-ftpd (SER tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 972/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 975/cupsd tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 1257/master tcp 0 0 0.0.0.0:8090 0.0.0.0:* LISTEN 636/lscpd (lscpd - tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 1015/dovecot tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN 1015/dovecot tcp6 0 0 :::3306 :::* LISTEN 1053/mysqld tcp6 0 0 :::3307 :::* LISTEN 1211/mysqld tcp6 0 0 :::587 :::* LISTEN 1257/master tcp6 0 0 :::110 :::* LISTEN 1015/dovecot tcp6 0 0 :::143 :::* LISTEN 1015/dovecot tcp6 0 0 :::111 :::* LISTEN 1/systemd tcp6 0 0 :::80 :::* LISTEN 990/httpd tcp6 0 0 :::465 :::* LISTEN 1257/master tcp6 0 0 :::53 :::* LISTEN 1404/pdns_server tcp6 0 0 :::21 :::* LISTEN 1064/pure-ftpd (SER tcp6 0 0 :::22 :::* LISTEN 972/sshd tcp6 0 0 ::1:631 :::* LISTEN 975/cupsd tcp6 0 0 :::25 :::* LISTEN 1257/master tcp6 0 0 :::993 :::* LISTEN 1015/dovecot tcp6 0 0 :::995 :::* LISTEN 1015/dovecot
Ka ilele tebulu ụzọ kernel, jiri ọkọlọtọ -r (nke dabara na ịme iwu ụzọ n'elu).
$ netstat -r Destination Gateway Genmask Flags MSS Window irtt Iface default gateway 0.0.0.0 UG 0 0 0 enp0s3 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 enp0s3 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
Rịba ama: Ọ bụ ezie na Netstat bụ ngwá ọrụ dị ukwuu, ọ bụzi ihe na-abaghị uru (nke a kwụsịrị), ndochi ya bụ iwu ss nke a kọwara n'okpuru ebe a.
ss (ọnụọgụ sọket) bụ akụrụngwa iwu siri ike iji nyochaa sọket. Ọ na-atụfu ọnụ ọgụgụ sọket ma gosipụta ozi yiri netstat. Na mgbakwunye, ọ na-egosikwu TCP na ozi steeti ma e jiri ya tụnyere ihe ndị ọzọ yiri ya.
Ihe atụ na-esonụ na-egosi otu esi edepụta ọdụ ụgbọ mmiri TCP niile (sockets) na-emeghe na ihe nkesa.
$ ss -ta State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 100 *:submission *:* LISTEN 0 128 127.0.0.1:fmpro-internal *:* LISTEN 0 100 *:pop3 *:* LISTEN 0 100 *:imap *:* LISTEN 0 128 *:sunrpc *:* LISTEN 0 100 *:urd *:* LISTEN 0 128 *:domain *:* LISTEN 0 9 *:ftp *:* LISTEN 0 128 *:ssh *:* LISTEN 0 128 127.0.0.1:ipp *:* LISTEN 0 100 *:smtp *:* LISTEN 0 128 *:8090 *:* LISTEN 0 100 *:imaps *:* LISTEN 0 100 *:pop3s *:* ESTAB 0 0 192.168.0.104:ssh 192.168.0.103:36398 ESTAB 0 0 127.0.0.1:34642 127.0.0.1:opsession-prxy ESTAB 0 0 127.0.0.1:34638 127.0.0.1:opsession-prxy ESTAB 0 0 127.0.0.1:34644 127.0.0.1:opsession-prxy ESTAB 0 0 127.0.0.1:34640 127.0.0.1:opsession-prxy LISTEN 0 80 :::mysql :::* ...
Iji gosi njikọ TCP niile na-arụ ọrụ yana oge ha, mee iwu na-esonụ.
$ ss -to
NC (NetCat) nke a na-akpọkwa Network Swiss Army Mma, bụ ihe dị ike eji eme ihe fọrọ nke nta ka ọ bụrụ ọrụ ọ bụla metụtara TCP, UDP, ma ọ bụ UNIX-ngalaba oghere. A na-eji ya mepee njikọ TCP, gee ntị na TCP na-ezighị ezi. na ọdụ ụgbọ mmiri UDP, mee nyocha ọdụ ụgbọ mmiri yana ndị ọzọ.
Ịnwekwara ike iji ya dị ka proxy TCP dị mfe, maka nyocha daemon netwọk, iji lelee ma enwere ike iru ọdụ ụgbọ mmiri dịpụrụ adịpụ, yana ọtụtụ ndị ọzọ. Ọzọkwa, ị nwere ike were nc yana iwu pv nyefee faịlụ n'etiti kọmputa abụọ.
[Ị nwekwara ike ịmasị: 8 Netcat (nc) Iwu na ihe atụ]
Ihe atụ na-esonụ ga-egosi otu esi enyocha ndepụta ọdụ ụgbọ mmiri.
$ nc -zv server2.tecmint.lan 21 22 80 443 3000
Ị nwekwara ike ịkọwapụta ọdụ ụgbọ mmiri dị iche iche dịka egosiri.
$ nc -zv server2.tecmint.lan 20-90
Ihe atụ na-esonụ na-egosi otu esi eji nc mepee njikọ TCP na ọdụ ụgbọ mmiri 5000 na server2.tecmint.lan, na-eji ọdụ ụgbọ mmiri 3000 dị ka ọdụ ụgbọ mmiri, na oge nkwụsị nke 10 sekọnd.
$ nc -p 3000 -w 10 server2.tecmint.lan 5000
Nmap (Network Mapper) bụ ngwá ọrụ dị ike ma dị oke ọnụ maka ndị na-ahụ maka sistemụ Linux/netwọkụ. A na-eji ya chịkọta ozi gbasara otu onye ọbịa ma ọ bụ nyochaa netwọkụ netwọkụ niile. A na-ejikwa Nmap mee nyocha nchekwa, nyocha netwọkụ na ịchọta ọdụ ụgbọ mmiri mepere emepe na ndị ọbịa dịpụrụ adịpụ na ọtụtụ ndị ọzọ.
Ị nwere ike nyochaa onye ọbịa site na iji aha nnabata ma ọ bụ adreesị IP ya, dịka ọmụmaatụ.
$ nmap google.com Starting Nmap 6.40 ( http://nmap.org ) at 2018-07-12 09:23 BST Nmap scan report for google.com (172.217.166.78) Host is up (0.0036s latency). rDNS record for 172.217.166.78: bom05s15-in-f14.1e100.net Not shown: 998 filtered ports PORT STATE SERVICE 80/tcp open http 443/tcp open https Nmap done: 1 IP address (1 host up) scanned in 4.92 seconds
N'aka nke ọzọ, jiri adreesị IP dịka egosiri.
$ nmap 192.168.0.103 Starting Nmap 6.40 ( http://nmap.org ) at 2018-07-12 09:24 BST Nmap scan report for 192.168.0.103 Host is up (0.000051s latency). Not shown: 994 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 902/tcp open iss-realsecure 4242/tcp open vrml-multi-use 5900/tcp open vnc 8080/tcp open http-proxy MAC Address: 28:D2:44:EB:BD:98 (Lcfc(hefei) Electronics Technology Co.) Nmap done: 1 IP address (1 host up) scanned in 0.13 seconds
Gụọ akụkọ anyị na-esote bara uru na iwu nmap.
- Otu esi eji Nmap Script Engine (NSE) Scripts na Linux
Ihe nyocha DNS
iwu nnabata bụ ihe dị mfe maka ịme nyocha DNS, ọ na-atụgharị aha nnabata na adreesị IP yana ọzọ.
$ host google.com google.com has address 172.217.166.78 google.com mail is handled by 20 alt1.aspmx.l.google.com. google.com mail is handled by 30 alt2.aspmx.l.google.com. google.com mail is handled by 40 alt3.aspmx.l.google.com. google.com mail is handled by 50 alt4.aspmx.l.google.com. google.com mail is handled by 10 aspmx.l.google.com.
igwu ( ngalaba ozi groper) bụkwa ihe ọzọ dị mfe nyocha DNS, nke a na-eji jụọ ajụjụ metụtara DNS dị ka A Record, CNAME, MX Record wdg, dịka ọmụmaatụ:
$ dig google.com ; <<>> DiG 9.9.4-RedHat-9.9.4-51.el7 <<>> google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23083 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 13, ADDITIONAL: 14 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 72 IN A 172.217.166.78 ;; AUTHORITY SECTION: com. 13482 IN NS c.gtld-servers.net. com. 13482 IN NS d.gtld-servers.net. com. 13482 IN NS e.gtld-servers.net. com. 13482 IN NS f.gtld-servers.net. com. 13482 IN NS g.gtld-servers.net. com. 13482 IN NS h.gtld-servers.net. com. 13482 IN NS i.gtld-servers.net. com. 13482 IN NS j.gtld-servers.net. com. 13482 IN NS k.gtld-servers.net. com. 13482 IN NS l.gtld-servers.net. com. 13482 IN NS m.gtld-servers.net. com. 13482 IN NS a.gtld-servers.net. com. 13482 IN NS b.gtld-servers.net. ;; ADDITIONAL SECTION: a.gtld-servers.net. 81883 IN A 192.5.6.30 b.gtld-servers.net. 3999 IN A 192.33.14.30 c.gtld-servers.net. 14876 IN A 192.26.92.30 d.gtld-servers.net. 85172 IN A 192.31.80.30 e.gtld-servers.net. 95861 IN A 192.12.94.30 f.gtld-servers.net. 78471 IN A 192.35.51.30 g.gtld-servers.net. 5217 IN A 192.42.93.30 h.gtld-servers.net. 111531 IN A 192.54.112.30 i.gtld-servers.net. 93017 IN A 192.43.172.30 j.gtld-servers.net. 93542 IN A 192.48.79.30 k.gtld-servers.net. 107218 IN A 192.52.178.30 l.gtld-servers.net. 6280 IN A 192.41.162.30 m.gtld-servers.net. 2689 IN A 192.55.83.30 ;; Query time: 4 msec ;; SERVER: 192.168.0.1#53(192.168.0.1) ;; WHEN: Thu Jul 12 09:30:57 BST 2018 ;; MSG SIZE rcvd: 487
Nslookup bụkwa ngwa iwu na-ewu ewu iji jụọ sava DNS ma na-emekọrịta ihe na nke anaghị emekọrịta ihe. A na-eji ya jụọ ajụjụ ndekọ akụ DNS (RR). Ị nwere ike ịchọta ndekọ A (adreesị IP) nke ngalaba dịka egosiri.
$ nslookup google.com Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: Name: google.com Address: 172.217.166.78
Ị nwekwara ike ịme nyocha ngalaba azụ dịka egosiri.
$ nslookup 216.58.208.174 Server: 192.168.0.1 Address: 192.168.0.1#53 Non-authoritative answer: 174.208.58.216.in-addr.arpa name = lhr25s09-in-f14.1e100.net. 174.208.58.216.in-addr.arpa name = lhr25s09-in-f174.1e100.net. Authoritative answers can be found from: in-addr.arpa nameserver = e.in-addr-servers.arpa. in-addr.arpa nameserver = f.in-addr-servers.arpa. in-addr.arpa nameserver = a.in-addr-servers.arpa. in-addr.arpa nameserver = b.in-addr-servers.arpa. in-addr.arpa nameserver = c.in-addr-servers.arpa. in-addr.arpa nameserver = d.in-addr-servers.arpa. a.in-addr-servers.arpa internet address = 199.180.182.53 b.in-addr-servers.arpa internet address = 199.253.183.183 c.in-addr-servers.arpa internet address = 196.216.169.10 d.in-addr-servers.arpa internet address = 200.10.60.53 e.in-addr-servers.arpa internet address = 203.119.86.101 f.in-addr-servers.arpa internet address = 193.0.9.1
Linux Network Packet Analyzers
Tcpdump bụ sniffer netwọọdụ iwu dị ike ma na-ejikarị. A na-eji ya weghara ma nyochaa ngwugwu TCP/IP ebufe ma ọ bụ nata na netwọk na otu interface.
Iji weghara ngwugwu site na interface enyere, kọwaa ya site na iji -i nhọrọ.
$ tcpdump -i eth1 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes 09:35:40.287439 IP linux-console.net.ssh > 192.168.0.103.36398: Flags [P.], seq 4152360356:4152360552, ack 306922699, win 270, options [nop,nop,TS val 2211778668 ecr 2019055], length 196 09:35:40.287655 IP 192.168.0.103.36398 > linux-console.net.ssh: Flags [.], ack 196, win 5202, options [nop,nop,TS val 2019058 ecr 2211778668], length 0 09:35:40.288269 IP linux-console.net.54899 > gateway.domain: 43760+ PTR? 103.0.168.192.in-addr.arpa. (44) 09:35:40.333763 IP gateway.domain > linux-console.net.54899: 43760 NXDomain* 0/1/0 (94) 09:35:40.335311 IP linux-console.net.52036 > gateway.domain: 44289+ PTR? 1.0.168.192.in-addr.arpa. (42)
Iji weghara otu ọnụ ọgụgụ nke ngwugwu, jiri nhọrọ -c tinye nọmba achọrọ.
$ tcpdump -c 5 -i eth1
Ịnwekwara ike ijide ma chekwaa ngwugwu na faịlụ maka nyocha ọzọ, jiri ọkọlọtọ -w kọwaa faịlụ mmepụta.
$ tcpdump -w captured.pacs -i eth1
Wireshark bụ ngwa ewu ewu, dị ike, dị mfe, yana dị mfe iji maka ịdepụta na nyocha ngwugwu n'ime netwọọkụ nwere ngwungwu, ozugbo.
Ị nwekwara ike ichekwa data o weghaara na faịlụ maka nyocha ọzọ. Ndị na-ahụ maka sistemụ na ndị injinia netwọk na-eji ya iji nyochaa na nyochaa ngwugwu maka ebumnuche nchekwa na nchọpụta nsogbu.
bmon bụ ihe siri ike, nleba anya netwọkụ dabere na usoro iwu maka sistemu Unix, ọ na-ejide ọnụ ọgụgụ metụtara ịkparịta ụka n'Ịntanet wee bipụta ya n'anya n'ụdị enyi mmadụ. Ọ bụ ihe nleba anya bandwit nke a pụrụ ịdabere na ya na nke dị irè na ihe nleba anya.
Ngwaọrụ Njikwa Firewall Linux
iptables bụ ngwá ọrụ ahịrị iwu maka ịhazi, idowe, na inyocha tebụl nzacha IP na ụkpụrụ NAT. A na-eji ya iji melite na jikwaa Linux firewall (Netfilter). Ọ na-enye gị ohere ịdepụta iwu nzacha dị adị; tinye ma ọ bụ hichapụ ma ọ bụ gbanwee iwu nzacha ngwugwu; depụta ọnụ ọgụgụ otu usoro nke iwu nzacha ngwugwu.
Ị nwere ike ịmụta otu esi eji Iptables maka ebumnuche dị iche iche site na ntuziaka anyị dị mfe ma zuru oke.
Firewalld bụ daemon dị ike ma dị ike iji jikwaa firewall Linux (Netfilter), dị ka iptables. Ọ na-eji zones netwọk kama INPUT, OUTPUT, na FORWARD CHAINS na iptables. Na nkesa Linux ugbu a dị ka RHEL/CentOS 7 na Fedora 21+, a na-eji firewalld dochie iptables nke ọma.
Iji malite na firewalld, kpọtụrụ ntuziaka ndị a edepụtara n'okpuru:
Ihe dị mkpa: A ka na-akwado Iptables ma enwere ike itinye ya na njikwa ngwugwu YUM. Otú ọ dị, ịnweghị ike iji Firewalld na iptables n'otu oge na otu ihe nkesa - ị ga-ahọrọ otu.
UFW bụ ngwa ọrụ nhazi nchekwa nchekwa ama ama na nkesa Debian na Ubuntu Linux. A na-eji ya mee ka/gbanyụọ firewall sistemụ, tinye/ihichapụ/gbanwee/tọgharịa iwu nzacha ngwugwu, yana ọtụtụ ndị ọzọ.
Ka ịlele ọkwa UFW firewall, pịnye.
$ sudo ufw status
Ọ bụrụ na ọkụ ọkụ UFW adịghị arụ ọrụ, ịnwere ike ịgbalite ma ọ bụ mee ya site na iji iwu na-esonụ.
$ sudo ufw enable
Iji gbanyụọ UFW firewall, jiri iwu na-esonụ.
$ sudo ufw disable
Gụọ akụkọ anyị Otu esi edozi ọkụ ọkụ UFW na Ubuntu na Debian.
Ọ bụrụ na ịchọrọ ịchọta ozi ndị ọzọ gbasara otu mmemme, ị nwere ike ịlele ibe nwoke ya dị ka egosiri.
$ man programs_name
Nke ahụ bụ ihe niile ugbu a! N'ime ntuziaka a zuru oke, anyị tụlere ụfọdụ ngwa ọrụ ahịrị iwu na akụrụngwa maka njikwa netwọkụ na Linux, n'okpuru ụdị dị iche iche, maka ndị na-ahụ maka sistemụ, yana bara uru maka ndị na-ahụ maka netwọkụ/ndị injinia oge niile.
Ị nwere ike ịkekọrịta echiche gị gbasara ntuziaka a site na ụdị nkọwa n'okpuru. Ọ bụrụ na anyị agbagharala ngwaọrụ/ọrụ ịkparịta ụka n'Ịntanet Linux ọ bụla a na-ejikarị ma ọ bụ ozi ọ bụla bara uru, mee ka anyị mara.