18 KiB
Basic Linux Networking Commands
Indirizzo IP
Il comando ip --color a permette di visualizzare l'indirizzo ip della macchina:
ip --color a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
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
[...]
3: wlp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
[...]
inet 192.168.1.127/24 brd 192.168.1.255 scope global noprefixroute wlp4s0
valid_lft forever preferred_lft forever
inet6 fe80::497e:1f53:1218:37cc/64 scope link noprefixroute
valid_lft forever preferred_lft forever
Impostare un IP statico
vim /etc/network/interfaces
auto eth0
iface eth0 inet static
address 192.168.1.56
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameservers 5.2.75.75 1.1.1.1
systemctl restart networking
Nel caso si volesse impostare un IP statico temporaneamente:
ip addr add 172.19.1.10/24 dev eth0
Rimuovere un IP da un interfaccia
ip addr del 172.19.1.10/24 dev eth0
Abilitare/disabilitare un interfaccia
ip link set eth0 up
ip link set eth0 down
Tabella di routing
ip route show
Aggiungere o rimuovere una rotta statica
ip route add 172.19.1.0/24 dev eth0
ip route del 172.19.1.0/24 dev eth0
Per aggiungere il default gateway:
ip route add default via 172.17.0.1
per rimuoverlo: ip route del default
traceroute
Col comando traceroute è possibile identificare il percorso intrapreso dai pacchetti per raggiungere l'host.
traceroute duckduckgo.com
traceroute to duckduckgo.com (40.114.177.156), 30 hops max, 60 byte packets
1 _gateway (192.168.1.1) 4.449 ms 11.289 ms 12.478 ms
2 pppoe-server.net.ngi.it (81.174.0.21) 18.152 ms 19.602 ms 21.332 ms
3 10.222.163.138 (10.222.163.138) 38.414 ms 37.719 ms 48.982 ms
4 10.40.83.137 (10.40.83.137) 50.339 ms 48.975 ms 50.969 ms
5 * * *
6 ae70-0.mil30-96cbe-1a.ntwk.msn.net (104.44.37.3) 52.354 ms 28.915 ms 25.263 ms
7 ae22-0.ear01.zrh20.ntwk.msn.net (104.44.235.8) 30.643 ms 39.978 ms 41.664 ms
8 be-20-0.ibr01.zrh20.ntwk.msn.net (104.44.33.81) 61.505 ms 62.187 ms be-21-0.ibr02.zrh20.ntwk.msn.net (104.44.33.83) 77.807 ms
9 be-7-0.ibr01.zrh21.ntwk.msn.net (104.44.30.69) 67.861 ms be-19-0.ibr02.mrs20.ntwk.msn.net (104.44.29.101) 76.403 ms be-7-0.ibr01.zrh21.ntwk.msn.net (104.44.30.69) 67.809 ms
10 be-2-0.ibr01.fra23.ntwk.msn.net (104.44.16.141) 55.156 ms 71.792 ms 71.739 ms
11 be-2-0.ibr04.bl7.ntwk.msn.net (104.44.7.77) 58.408 ms 53.057 ms be-4-0.ibr02.ams21.ntwk.msn.net (104.44.17.55) 53.295 ms
12 ae120-0.icr01.ams21.ntwk.msn.net (104.44.22.242) 47.145 ms ae100-0.icr01.ams21.ntwk.msn.net (104.44.22.234) 45.453 ms ae106-0.icr04.ams21.ntwk.msn.net (104.44.23.245) 62.217 ms
Per impostazione predefinita, traceroute utilizzerà IPv4, ma è possibile modificare questo comportamento utilizzando IPv6 con l'opzione -6.
ping
Il comando ping (Packet Internet Groper) può essere considerato uno dei comandi più importanti durante la risoluzione dei problemi della rete, in quanto è il modo più comune per controllare la connettività tra host.
ping 5.2.75.75
PING 5.2.75.75 (5.2.75.75) 56(84) bytes of data.
64 bytes from 5.2.75.75: icmp_seq=1 ttl=55 time=67.5 ms
64 bytes from 5.2.75.75: icmp_seq=2 ttl=55 time=132 ms
64 bytes from 5.2.75.75: icmp_seq=3 ttl=55 time=78.5 ms
64 bytes from 5.2.75.75: icmp_seq=4 ttl=55 time=50.5 ms
64 bytes from 5.2.75.75: icmp_seq=5 ttl=55 time=52.0 ms
64 bytes from 5.2.75.75: icmp_seq=6 ttl=55 time=74.6 ms
64 bytes from 5.2.75.75: icmp_seq=7 ttl=55 time=59.9 ms
64 bytes from 5.2.75.75: icmp_seq=8 ttl=55 time=51.4 ms
64 bytes from 5.2.75.75: icmp_seq=9 ttl=55 time=54.9 ms
Con l'opzione -c è possibile specificare il numero di pacchetti da inviare.
dig
Il comando dig (Domain Information Groper) viene utilizzato per recuperare tutte le informazioni necessarie sul server DNS.
È facilmente installabile col comando sudo apt install dnsutils.
dig lealternative.net
; <<>> DiG 9.18.12-1-Debian <<>> lealternative.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39808
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;lealternative.net. IN A
;; ANSWER SECTION:
lealternative.net. 60 IN A 84.16.89.21
;; Query time: 83 msec
;; SERVER: 45.90.28.222#53(45.90.28.222) (UDP)
;; WHEN: Sun Mar 12 17:21:46 CET 2023
;; MSG SIZE rcvd: 62
dig @5.2.75.75 lealternative.net
; <<>> DiG 9.18.12-1-Debian <<>> @5.2.75.75 lealternative.net
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 762
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1472
;; QUESTION SECTION:
;lealternative.net. IN A
;; ANSWER SECTION:
lealternative.net. 600 IN A 84.16.89.21
;; Query time: 227 msec
;; SERVER: 5.2.75.75#53(5.2.75.75) (UDP)
;; WHEN: Sun Mar 12 17:22:06 CET 2023
;; MSG SIZE rcvd: 62
Dopo la @ è possibile specificare un server DNS.
host
Il comando host viene utilizzato principalmente per ottenere l'indirizzo IP di un dominio specifico.
host lealternative.net
;; communications error to 45.90.28.222#53: timed out
lealternative.net has address 84.16.89.21
lealternative.net has IPv6 address 2001:1600:3:5::722
lealternative.net mail is handled by 5 mail.protonmail.ch.
lealternative.net mail is handled by 10 mailsec.protonmail.ch.
host beopen.neocities.org
beopen.neocities.org has address 198.51.233.2
beopen.neocities.org has IPv6 address 2620:2:6000::a:1
Allo stesso modo, è possibile utilizzare un indirizzo IP per recuperare il nome di dominio:
host 5.2.75.75
75.75.2.5.in-addr.arpa domain name pointer nl.ahadns.net.
whois
Il whois può aiutare a trovare informazioni sui domini registrati, indirizzi IP e molto altro ancora.
sudo apt install whois
Ecco un esempio del comando:
whois androidworld.it
Domain: androidworld.it
Status: ok
Signed: no
Created: 2009-03-17 11:31:57
Last Update: 2022-09-09 12:04:08
Expire Date: 2023-09-08
Registrant
Organization: Mondadori Media S.p.A.
Address: Via Bianca di Savoia 12
Milano
20122
MI
IT
Created: 2021-06-14 17:22:49
Last Update: 2022-09-07 12:29:28
Admin Contact
Name: Andrea Canepa
Organization: Mondadori Media S.p.A.
Address: Via Bianca di Savoia 12
Milano
20122
MI
IT
Created: 2021-06-14 17:22:53
Last Update: 2022-09-07 12:30:05
Technical Contacts
Name: Technical Manager
Organization: BARBERO and Associates Ltd
Address: 3 Shortlands, 4th floor
London
W6 8DA
GB
GB
Created: 2014-10-09 11:19:42
Last Update: 2019-09-19 10:00:50
Registrar
Organization: BARBERO & Associates Ltd
Name: BARBERO-REG
Web: https://www.barbero.co.uk
DNSSEC: yes
Nameservers
ns-666.awsdns-19.net
ns-1703.awsdns-20.co.uk
ns-74.awsdns-09.com
In alternativa, si può utilizzare un indirizzo IP invece di un dominio e si otterranno gli stessi dettagli.
ifplugstatus
sudo apt install ifplugd
Viene utilizzato per rilevare lo stato del collegamento della porta ethernet:
sudo ifplugstatus
lo: link beat detected
eno1: unplugged
wlp4s0: link beat detected
nmcli
È possibile utilizzare il comando nmcli per monitorare lo stato di connettività delle interfacce di rete:
nmcli dev status
DEVICE TYPE STATE CONNECTION
wlp4s0 wifi collegato WiFi
lo loopback connected (externally) lo
p2p-dev-wlp4s0 wifi-p2p disconnesso --
eno1 ethernet non disponibile --
Se utilizzato senza alcuna opzione, stamperà a video più informazioni.
nmap
nmap consente di effettuare port scanning, cioè individuazione di porte aperte su un computer bersaglio o anche su range di indirizzi IP, in modo da determinare quali servizi di rete siano disponibili.
Può anche essere utilizzato anche per scoprire le regole delle porte, la versione del sistema operativo, le vulnerabilità presenti...
nmap lealternative.net
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 17:44 CET
Nmap scan report for lealternative.net (84.16.89.21)
Host is up (0.048s latency).
Other addresses for lealternative.net (not scanned): 2001:1600:3:5::722
Not shown: 998 filtered tcp ports (no-response)
PORT STATE SERVICE
80/tcp open http
443/tcp open https
Nmap done: 1 IP address (1 host up) scanned in 11.23 seconds
Scansionare le porte aperte
nmap scanme.nmap.org
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:19 CET
Nmap scan report for scanme.nmap.org (45.33.32.156)
Host is up (0.19s latency).
Other addresses for scanme.nmap.org (not scanned): 2600:3c01::f03c:91ff:fe18:bb2f
Not shown: 995 closed tcp ports (conn-refused)
PORT STATE SERVICE
22/tcp open ssh
25/tcp filtered smtp
80/tcp open http
9929/tcp open nping-echo
31337/tcp open Elite
Nmap done: 1 IP address (1 host up) scanned in 21.49 seconds
Se si va di fretta e è necessario finire la scansione il prima possibile, si può utilizzare l'opzione -F
Scansionare più host
Potrebbe essere necessario eseguire la scansione di più host e nmap offre vari modi per eseguire tale scansione, tra cui usare i caratteri jolly:
nmap -F 192.168.1.*
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:25 CET
Nmap scan report for 192.168.1.1
Host is up (0.065s latency).
Not shown: 97 closed tcp ports (conn-refused)
PORT STATE SERVICE
22/tcp open ssh
53/tcp open domain
80/tcp open http
Nmap scan report for 192.168.1.21
Host is up (0.0077s latency).
Not shown: 96 closed tcp ports (conn-refused)
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
6000/tcp open X11
6001/tcp open X11:1
Nmap scan report for 192.168.1.27
Host is up (0.015s latency).
All 100 scanned ports on 192.168.1.27 are in ignored states.
Not shown: 100 closed tcp ports (conn-refused)
Nmap done: 256 IP addresses (6 hosts up) scanned in 17.44 seconds
Se durante la scansione si volesse escludere un host utilizzare la seguente sintassi: nmap 192.168.1.* --exclude 192.168.1.6
Scansionare porte specifiche
È possibile specificare una o più porte o un intervallo:
nmap -p 443,80 scanme.nmap.org
nmap -p 20-80 scanme.nmap.org
Per ottenere maggiorni informazioni sulle porte:
nmap -sV scanme.nmap.org
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:30 CET
Nmap scan report for scanme.nmap.org (45.33.32.156)
Host is up (0.19s latency).
Other addresses for scanme.nmap.org (not scanned): 2600:3c01::f03c:91ff:fe18:bb2f
Not shown: 995 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.13 (Ubuntu Linux; protocol 2.0)
25/tcp filtered smtp
80/tcp open http Apache httpd 2.4.7 ((Ubuntu))
9929/tcp open nping-echo Nping echo
31337/tcp open tcpwrapped
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 34.59 seconds
Scansioni stealth
Le scansioni stealth vengono eseguite quando si desidera bypassare il firewall.
sudo nmap -sS scanme.nmap.org
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:34 CET
Nmap scan report for scanme.nmap.org (45.33.32.156)
Host is up (0.29s latency).
Other addresses for scanme.nmap.org (not scanned): 2600:3c01::f03c:91ff:fe18:bb2f
Not shown: 995 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp open ssh
25/tcp filtered smtp
80/tcp open http
9929/tcp open nping-echo
31337/tcp open Elite
Nmap done: 1 IP address (1 host up) scanned in 30.03 seconds
Informazioni sull'OS
Il comando nmap può essere utilizzato anche per trovare informazioni sul sistema operativo dell'host con l'opzione -A:
nmap -A scanme.nmap.org
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:36 CET
Nmap scan report for scanme.nmap.org (45.33.32.156)
Host is up (0.19s latency).
Other addresses for scanme.nmap.org (not scanned): 2600:3c01::f03c:91ff:fe18:bb2f
Not shown: 995 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.13 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 1024 ac00a01a82ffcc5599dc672b34976b75 (DSA)
| 2048 203d2d44622ab05a9db5b30514c2a6b2 (RSA)
| 256 9602bb5e57541c4e452f564c4a24b257 (ECDSA)
|_ 256 33fa910fe0e17b1f6d05a2b0f1544156 (ED25519)
25/tcp filtered smtp
80/tcp open http Apache httpd 2.4.7 ((Ubuntu))
|_http-server-header: Apache/2.4.7 (Ubuntu)
|_http-favicon: Nmap Project
|_http-title: Go ahead and ScanMe!
9929/tcp open nping-echo Nping echo
31337/tcp open tcpwrapped
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 46.43 seconds
host attivi
nmap -sP 192.168.1.*
Starting Nmap 7.93 ( https://nmap.org ) at 2023-03-12 18:39 CET
Nmap scan report for 192.168.1.1
Host is up (0.032s latency).
Nmap scan report for 192.168.1.21
Host is up (0.058s latency).
Nmap scan report for 192.168.1.24
Host is up (0.28s latency).
Nmap scan report for 192.168.1.27
Host is up (0.12s latency).
Nmap scan report for 192.168.1.34
Host is up (0.19s latency).
Nmap scan report for 192.168.1.101
Host is up (0.19s latency).
Nmap scan report for 192.168.1.103
Host is up (0.26s latency).
Nmap scan report for 192.168.1.119
Host is up (0.18s latency).
Nmap scan report for 192.168.1.127
Host is up (0.00012s latency).
Nmap done: 256 IP addresses (9 hosts up) scanned in 13.19 seconds
nmap -sP 192.168.1.0/24/
speedtest-cli
Come suggerisce il nome, questo comando permette di eseguire uno speedtest della rete.
sudo apt install speedtest-cli
speedtest-cli
Retrieving speedtest.net configuration...
Testing from EOLO (146.241.81.101)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by STEL s.r.l. (Ferrara) [179.97 km]: 108.923 ms
Testing download speed................................................................................
Download: 14.33 Mbit/s
Testing upload speed......................................................................................................
Upload: 2.97 Mbit/s
vnstat
vnstat -i wlp4s0 -l
Permette di monitorare il traffico di rete. L'opzione -i specifica l'interfaccia, mentre -l è utile per il monitoraggio dal vivo.
netstat
netstat è una delle utility più popolari per monitorare le connessioni sulla rete.
Consente di monitorare facilmente le connessioni in entrata e in uscita, le porte in ascolto e altro ancora.
Per visualizzare tutte le porte in ascolto, utilizzare l'opzione -l:
netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:ipp 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:ipp [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
udp 0 0 0.0.0.0:mdns 0.0.0.0:*
udp 0 0 0.0.0.0:55417 0.0.0.0:*
udp 0 0 0.0.0.0:49399 0.0.0.0:*
udp 0 0 0.0.0.0:631 0.0.0.0:*
udp 0 0 0.0.0.0:21027 0.0.0.0:*
udp6 0 0 [::]:mdns [::]:*
udp6 0 0 [::]:22000 [::]:*
udp6 0 0 [::]:39924 [::]:*
udp6 0 0 [::]:58803 [::]:*
udp6 0 0 [::]:21027 [::]:*
raw 0 0 0.0.0.0:255 0.0.0.0:* 7
raw6 0 0 [::]:ipv6-icmp [::]:* 7
Per visualizzare tutte le porte utilizzare il comando netstat -a.
Porte TCP e UDP
netstat -lt
netstat -lu
I comandi precedenti permettono di elencare le porte TCP o UDP in ascolto nel sistema.