Find the IP address of the client in an SSH session

问题

I have a script that is to be run by a person that logs in to the server with SSH.

Is there a way to find out automatically what IP address the user is connecting from?

Of course, I could ask the user (it is a tool for programmers, so no problem with that), but it would be cooler if I just found out.

回答1:

Check if there is an environment variable called:

$SSH_CLIENT

$SSH_CONNECTION

(or any other environment variables) which gets set when the user logs in. Then process it using the user login script.

Extract the IP:

$ echo $SSH_CLIENT | awk '{ print $1}'
1.2.3.4
$ echo $SSH_CONNECTION | awk '{print $1}'
1.2.3.4

回答2:

You could use the command:

server:~# pinky

that will give to you somehting like this:

Login      Name                 TTY    Idle   When                 Where 

root       root                 pts/0         2009-06-15 13:41     192.168.1.133

回答3:

Try the following to get just the IP address:

who am i|awk '{ print $5}'

回答4:

Just type the following command on your Linux machine:

who

回答5:

who am i | awk '{print $5}' | sed 's/[()]//g' | cut -f1 -d "." | sed 's/-/./g'


export DISPLAY=`who am i | awk '{print $5}' | sed 's/[()]//g' | cut -f1 -d "." | sed 's/-/./g'`:0.0

I use this to determine my DISPLAY variable for the session when logging in via ssh and need to display remote X.

回答6:

 who | cut -d"(" -f2 |cut -d")" -f1

回答7:

Improving on a prior answer. Gives ip address instead of hostname. --ips not available on OS X.

who am i --ips|awk '{print $5}' #ubuntu 14

more universal, change $5 to $6 for OS X 10.11:

WORKSTATION=`who -m|awk '{print $5}'|sed 's/[()]//g'`
WORKSTATION_IP=`dig +short $WORKSTATION`
if [[ -z "$WORKSTATION_IP" ]]; then WORKSTATION_IP="$WORKSTATION"; fi
echo $WORKSTATION_IP

回答8:

netstat -tapen | grep ssh | awk '{ print $4}'

回答9:

You can get it in a programmatic way via an SSH library (https://code.google.com/p/sshxcute)

public static String getIpAddress() throws TaskExecFailException{
    ConnBean cb = new ConnBean(host, username, password);
    SSHExec ssh = SSHExec.getInstance(cb);
    ssh.connect();
    CustomTask sampleTask = new ExecCommand("echo \"${SSH_CLIENT%% *}\"");
    String Result = ssh.exec(sampleTask).sysout;
    ssh.disconnect();   
    return Result;
}

回答10:

netstat will work (at the top something like this) tcp 0 0 10.x.xx.xx:ssh someipaddress.or.domainame:9379 ESTABLISHED

回答11:

netstat -tapen | grep ssh | awk '{ print $10}'

Output:

two # in my experiment

netstat -tapen | grep ssh | awk '{ print $4}'

gives the IP address.

Output:

127.0.0.1:22 # in my experiment

But the results are mixed with other users and stuff. It needs more work.

回答12:

Usually there is a log entry in /var/log/messages (or similar, depending on your OS) which you could grep with the username.

回答13:

Linux: who am i | awk '{print $5}' | sed 's/[()]//g'

AIX: who am i | awk '{print $6}' | sed 's/[()]//g'

回答14:

Search for SSH connections for "myusername" account;

Take first result string;

Take 5th column;

Split by ":" and return 1st part (port number don't needed, we want just IP):

netstat -tapen | grep "sshd: myusername" | head -n1 | awk '{split($5, a, ":"); print a[1]}'

Another way:

who am i | awk '{l = length($5) - 2; print substr($5, 2, l)}'

回答15:

Assuming he opens an interactive session (that is, allocates a pseudo terminal) and you have access to stdin, you can call an ioctl on that device to get the device number (/dev/pts/4711) and try to find that one in /var/run/utmp (where there will also be the username and the IP address the connection originated from).

回答16:

an older thread with a lot of answers, but none are quite what i was looking for, so i'm contributing mine:

sshpid=$$
sshloop=0
while [ "$sshloop" = "0" ]; do
        if [ "$(strings /proc/${sshpid}/environ | grep ^SSH_CLIENT)" ];
then
                read sshClientIP sshClientSport sshClientDport <<< $(strings /proc/${sshpid}/environ | grep ^SSH_CLIENT | cut -d= -f2)
                sshloop=1
        else
                sshpid=$(cat /proc/${sshpid}/status | grep PPid | awk '{print $2}')
                [ "$sshpid" = "0" ] && sshClientIP="localhost" && sshloop=1
        fi
done

this method is compatible with direct ssh, sudoed users, and screen sessions. it will trail up through the process tree until it finds a pid with the SSH_CLIENT variable, then record its IP as $sshClientIP. if it gets too far up the tree, it will record the IP as 'localhost' and leave the loop.

回答17:

One thumb up for @Nikhil Katre's answer :

Simplest command to get the last 10 users logged in to the machine is last|head.

To get all the users simply use last command

The one using who or pinky did what is basically asked. But But But they don't give historical sessions info.

Which might also be interesting if you want to know someone who has just logged in and logged out already when you start this checking.

if it is a multiuser system. I recommand add the user account you are looking for:

last | grep $USER | head

EDIT:

In my case, both $SSH_CLIENT and $SSH_CONNECTION do not exist.

回答18:

I'm getting the following output from who -m --ips on Debian 10:

root pts/0 Dec 4 06:45 123.123.123.123

Looks like a new column was added, so {print $5} or "take 5th column" attempts don't work anymore.

Try this:

who -m --ips | egrep -o '([0-9]{1,3}\.){3}[0-9]{1,3}'

Source:

@Yvan's comment on @AlexP's answer
@Sankalp's answer

回答19:

Simplest command to get the last 10 users logged in to the machine is last|head. To get all the users, simply use last command

来源：https://stackoverflow.com/questions/996231/find-the-ip-address-of-the-client-in-an-ssh-session

标签

Linux

networking

ssh

ip-address