24

Is there a bash command to find the IP address for an Ubuntu box? I need to find the IP address so I can ssh into the machine later.

19 Answers 19

32

/sbin/ifconfig -a

25

You can use:

/bin/ip addr
  • 3
    @opierce You have marked mpbloch's answer as correct, but as an FYI, you should be using this answer, as this is part of the iproute2 suite. ifconfig is being phased now. – jwbensley Jun 19 '13 at 15:03
  • 3
    You can make that shorter by just running ip a. – Gerald Kaszuba Dec 31 '13 at 20:42
19

If you have an internal address in use, checking

curl http://myip.dnsomatic.com

might be a good idea on unix shells.
Or, just plonk that URL into your browser.


If you get a different answer from the "ifconfig -a" result,
the ifconfig gave your internal address -- which will probably not work from outside.


Even if all seems fine, you could have a firewall in place that will disallow incoming ssh connections.
At which time you should try the port of interest from a browser on the machine at,

http://www.canyouseeme.org/

That will confirm connectivity through,

  • external IP address (showing it to you on that page)
  • NAT, Port Forwards
  • Firewalls
  • True, but if that is the case, there are probably no NAT/Port Forwarding rules in place to match ssh to whatever the internal IP is. – Kyle Brandt Jul 27 '09 at 18:25
  • @Kyle, Which can be added... – nik Jul 27 '09 at 18:30
  • 3
    +1 for curl http://myip.dnsomatic.com – JatSing Feb 16 '12 at 2:46
  • Similar to this, there is also curl ifconfig.me – jwbensley Jun 19 '13 at 15:04
18

/bin/hostname -i

  • 3
    In this case I would suggest using hostname --all-ip-addresses. Display all network addresses of the host. This option enumerates all configured addresses on all network interfaces. The loopback interface and IPv6 link-local addresses are omitted. Contrary to option -i, this option does not depend on name resolution. Do not make any assumptions about the order of the output. – lrkwz Jan 24 '14 at 11:36
  • 5
    Shorter alternative to @lrkwz's comment /bin/hostname -I – hanxue Apr 9 '14 at 8:58
  • Thanks @hanxue - this ought to be an answer of it's own - the shortest command with the cleanest output - just what I was looking for! In my experience (Ubuntu), /bin/hostname -i just gives 127.0.1.1, which is useless. – Roger Dueck Jun 27 '17 at 14:50
13
 curl icanhazip.com

tee hee!

From http://www.commandlinefu.com/commands/view/2966/return-external-ip

8
/sbin/ifconfig|grep inet|head -1|sed 's/\:/ /'|awk '{print $3}'

If you need your internal adress append your interface after ifconfig, e.g.

 /sbin/ifconfig eth0|grep inet|head -1|sed 's/\:/ /'|awk '{print $3}'
  • +1, this is exactly what I needed to solve a problem. Hurray for one-liners! – J. Polfer Feb 26 '10 at 18:53
  • +1 Without the head -1: /sbin/ifconfig|grep inet|sed 's/\:/ /'|awk 'NR==1 {print $3}' – joeslice Jul 7 '10 at 15:40
  • Thanks, it works on Debian but on OS X it doesn't work, returning some garbage. It would be great if we could come of with a line that works on both. Here is the output of ifconfig on OS X: gist.github.com/ssbarnea/5814657 – sorin Jun 19 '13 at 14:16
6

If you are behind a NAT, and need the public IP, use this:

wget -q -O - checkip.dyndns.org|sed -e 's/.Current IP Address: //' -e 's/<.$//'

taken from: http://www.go2linux.org/what-is-my-public-ip-address-with-linux

3

If you need to find out what the IP address of your router, you could run this command.

dig +short myip.opendns.com @208.67.222.222 @208.67.220.220

If you are using OpenDNS for your dns server, you could shorten it to:

dig +short myip.opendns.com

You could also use this command.

curl http://myip.dnsomatic.com
3

If you have multiple interfaces, could be useful to specify which one you want IP. if you want IPV4 address of interface 'eth0':

ip addr show dev eth0 | grep "inet " | awk '{ print $2 }' 

if you want IPV6 address of interface 'eth0':

ip addr show dev eth0 | grep "inet6 " | awk '{ print $2 }' 

if you want to search for an IP between two common interfaces of a laptop, wlan0 and eth0:

CURRENT_IP=''
for INTERFACE in wlan0 eth0; do
    if [ -z $CURRENT_IP ]; then
        CURRENT_IP=$(ip addr show dev $INTERFACE | grep "inet " | awk '{ print $2 }')
    fi
done
3

Just curl this page:

$ curl wtfismyip.com/text

  • And how exactly is this superior to the similar services already mentioned during these years? – Esa Jokinen Mar 29 '15 at 20:24
2

Here is a one line that works on Linux and OS X too, and it will return the first address that is not local:

ifconfig | sed -En 's/127.0.0.1//;s/.*inet (addr:)?(([0-9]*\.){3}[0-9]*).*/\2/p'

Send credits to https://stackoverflow.com/a/13322549/99834

2
LOCAL_IP=`/bin/hostname -I | sed 's/ //g'`
1

The simplest way to go about it is probably

ifconfig eth0

assuming the machine has a single IP address on the default wired interface - you might need

ifconfig wlan0

if it's on WiFi.

1
ip address show scope link

It will show you the IP address of living - has link - interfaces. But it is not a bash command. Bash has no ability to know about IP and network at all.

1

What I understand is you want to connect a remote ubuntu machine which has dynamic ip. Go dyndns.org site and open a free account. Then on the remote machine you need to install a dynamic ip tool.

sudo aptitude install dyndns-client

so you can ssh remote machine via

ssh username@yourdynamicnamealias.dyndns.org

So after configuration you will never need the remote machine ip address.

  • This is my preferred method for dealing with dynamic IPs. dyndns.org is a fantastic, free service. – John Barrett Aug 12 '09 at 8:40
1

Here is what I am using:

LC_ALL=C /sbin/ifconfig | awk '
    /inet addr/ {
        gsub("addr:","");
        if(($2!="127.0.0.1") && ($2!="0.0.0.0") && ($2!=""))
            { print $2 };
    }'
1

if you need just a single IP of given interface you can do:

ifconfig eth0 | grep "inet " | awk '{gsub("addr:","",$2);  print $2 }' 
0

I once golfed the extraction of IP address on Linux:

http://www.catonmat.net/blog/golfing-the-extraction-of-ip-addresses-from-ifconfig/

-2

The simplest way to get IP address:

Command: ifconfig

Example:

stalinrajindian@ubuntuserver:~$ ifconfig
enp0s3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.30.3.27  netmask 255.255.255.0  broadcast 172.30.3.255
        inet6 fe80::a00:27ff:fe8b:9986  prefixlen 64  scopeid 0x20<link>
        ether 08:00:27:8b:99:86  txqueuelen 1000  (Ethernet)
        RX packets 4876  bytes 1951791 (1.9 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 775  bytes 73783 (73.7 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 78  bytes 5618 (5.6 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 78  bytes 5618 (5.6 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
  • There is no reason to mention ssh in this answer. And using ifconfig was already suggested by 6 earlier answers. – kasperd Apr 16 '18 at 7:14

protected by Sven Apr 16 '18 at 9:42

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.