How do you stop ping in linux

How to stop a ping in linux

In case, it is missing from the system, you can install it using the following command in Terminal: $ sudo apt install iptables Block Ping Request To block ping requests to your system, type following command in Terminal: $ sudo iptables -A INPUT -p icmp —icmp-type 8 -j REJECT Where the A flag is used to add a rule in iptables and icmp-type 8 is the ICMP type number used for echo request . In order to unblock ping requests to your server, type the following command in Terminal: $ sudo iptables -D INPUT -p icmp —icmp-type 8 -j REJECT Where the D flag is used to delete a rule in iptables and icmp-type 8 is the ICMP type number used for an echo request .

How to stop the ping command if there is no reply after 1 sec? [duplicate]

while ! (ping -c 1 -W 1 8.8.8.8 > /dev/null); do sleep 1 done echo "< 1 sec reply received. exiting" 

How to Disable Ping Response (ICMP echo) in Linux all, You can use one of the following three ways (as root): Edit /etc/sysctl.conf Add the following line to your /etc/sysctl.conf: net.ipv4.icmp_echo_ignore_all=1 Then: sysctl -p Using iptables: iptables -I INPUT -p icmp --icmp-type echo-request -j DROP With cron Run crontab -e as root, then add …

How to Stop Ping in the Terminal

Step#1: Terminating a ping program First of all, let's open up the command prompt and let's issue a continuous ping. For that, we will type the ping command …

Unix & Linux: How to stop the ping command if there is

Unix & Linux : How to stop the ping command if there is no reply after 1 sec?Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaarWith

Linux Tip: How to use the ping command

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How to terminate ping <dest> &

First enter fg into same terminal that your ping command is running (it brings the process into the foreground), then press Ctrl + c to stop the process.

If it is your one and only background job you can kill it with kill %1 . If not sure you can list all your background jobs with jobs and use kill % where you replace n by the number of your ping job.

When you send a process to the background, whether by using ctrl - z or by & at the end of the command, you get an output in the following format: [index] process-id . If you send multiple processes to the background, the index will keep incrementing every time.

$ sleep 100 & [1] 41608 $ sleep 101 & [2] 41609 $ sleep 102 & [3] 41610 $ sleep 103 & [4] 41611 $ sleep 104 & [5] 41612 $ sleep 105 & [6] 41613 $ sleep 106 & [7] 41614 

In order to stop a specific one, you can either use kill or use fg followed by ctrl - c

Example using the previous output:

Linux - How to stop ping output?, Browse other questions tagged linux debian ping or ask your own question. The Overflow Blog At your next job interview, you ask the questions (Ep. 463)

How to block or unblock ping requests on Ubuntu Server 20.04 LTS

Ping is a network administration utility that is used to test the availability of a system on an IP network. Ping is also used to test the quality of the network connection by monitoring the round trip time and packet losses. On the other hand, network intruders and hackers also use ping to identify network subnets to find potential hosts or to perform ICMP flood attacks. Therefore, it is a good practice to block ping requests to your servers to prevent any kind of attack.

This article is about how to block ping requests to Linux Server. We will also describe how to unblock the ping requests in case you need to use ping for system administration and troubleshooting.

Prerequisites

Note: The commands discussed here have been tested on Ubuntu 20.04 LTS.

Block/unblock ping requests to Linux Server

Ping works by sending an ICMP packet (Echo request) to the destination system and then receives a response ICMP packet (Echo reply). In Linux, the ping command continues sending ICMP packets until you stop it using Ctrl+C.

In order to block ping requests, you will need to ignore/block the ICMP echo requests that are sent to your server. There are following two ways through which you can block/unblock ICMP echo requests to the Linux server.

Block/unblock ping requests through kernel parameters

Through kernel parameters, you can block ping requests either temporarily or permanently. Kernel parameters can be modified through sysctl command, /sys/proc directory, and /etc/sysctl.conf file.

Temporary block/unblock ping requests

The sysctl command in Linux is used to read and write kernel parameters in the /proc/sys directory. Using this command, we can set up kernel parameters to block/unblock ping requests. The kernel parameter net.ipv4.icmp_echo_ignore_all controls whether the system should respond to the ICMP echo request. The default value of it is ‘ 0’ which means to respond to the ICMP request.

Block Ping Request

In order to block ping request, issue the following command in Terminal:

This command sets the kernel parameter to ‘1’ which means to ignore all the ICMP requests.

Now all the ping requests to your system will be blocked and the sender will receive no response as shown in the below screenshot.

Unblock Ping Request

To unblock the ping requests, again run the same command by changing the parameter value to default ‘0’.

Alternatively, you can block the ping requests by changing the kernel parameter value in the /proc/sys directory using the echo command. However, to use this method, you will need to run the command as root.

In order to block ping request, first switch to root account using the following command in Terminal:

When prompted for the password, enter the password for root.

Then issue the following command in Terminal:

To unblock the ping requests, the command would be:

Permanently block ping requests

Kernel parameters can also be modified through the /etc/sysctl.conf file. This file will allow you to permanently block ping requests to your server.

Block Ping Request

In order to block ping request to your system, edit /etc/sysctl.conf file:

Then append the following line in the file:

Then issue the following command in Terminal to apply this configuration without reboot:

Unblock Ping Request

To unblock ping requests, edit the /etc/sysctl.conf file:

Then modify the value of net.ipv4.icmp_echo_ignore_all to ‘ 0’ :

Then issue the following command in Terminal to apply this configuration without reboot:

Block/unblock ping requests Using iptables

Iptables is a firewall utility in Linux that controls incoming and outgoing traffic based on certain rules. It comes preinstalled in the Ubuntu system. In case, it is missing from the system, you can install it using the following command in Terminal:

Block Ping Request

To block ping requests to your system, type following command in Terminal:

Where the A flag is used to add a rule in iptables and icmp-type 8 is the ICMP type number used for echo request .

The above command will add a rule in the firewall that will block any incoming ping requests to your system. By adding this rule, anyone sending the ping request to your system will see the “ Destination Port Unreachable ” message as shown in the below screenshot.

If you do not want this message to appear, use the following command replacing REJECT with DROP :

Now anyone sending the ping request to your system will see the following similar output:

Unblock Ping Request

In order to unblock ping requests to your server, type the following command in Terminal:

Where the D flag is used to delete a rule in iptables and icmp-type 8 is the ICMP type number used for an echo request .

In order to make these rules persistent after a system reboot, you will need iptables-persistent package. Issue the below command in Terminal to install iptables-persistent:

You will be asked to confirm whether you want to proceed with the installation or not. Hit y to proceed, after which the system will start the installation and once completed, it will be ready to use.

After adding or deleting any rule, issue the following commands in Terminal to make them survive the system reboot.

In order to view all the rules added to your iptables, issue the following command in Terminal:

That is all there is to it! In this article, we have discussed how to block/unblock ping requests to Linux Server either through the kernel parameters or through iptables utility. Hope this helps!

How to stop the ping command if there is no reply after, ping -c 1 8.8.8.8 while [ $? -ne 0 ] do sleep 0.5 ping -c 1 8.8.8.8 done. Now I'm not sure how this works, if the ping request got blocked on its way out (iptables or other) the command and the script will hang indefinitely. What I want is to stop waiting for a reply after 1 sec and send a new request. That until I get a reply …

Continues Pinging to background, save logs and show statistics

to show statistics and do not stop ping.

to show statistics as usual (e.g., when you press ctrl-c in terminal) and stop ping.

Command line - How to terminate ping, In order to stop a specific one, you can either use kill or use fg followed by ctrl-c. Example using the previous output: $ kill 41614 or $ fg 7 sleep 106 ^C

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