A tool commonly used to test the reachability of a given host, either on the internet or in a local network.

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13
votes
7answers
8k views

Faster way than ping for checking if computer online?

I'm writing a wake on lan script for a set of our lab computers. We have sqlite db with a list of the computer hostnames, IPs, and MACs and currently I ping each of them with '-c1' so it doesn't run ...
11
votes
3answers
1k views

How to redirect the output of any command?

I'm trying to write a simple script to monitor my network status, without all of ping's output: ping -q -c 1 google.com > /dev/null && echo online || echo offline The problem is that ...
10
votes
2answers
38k views

What could DUP mean when using ping?

What could DUP mean when using ping?
8
votes
2answers
2k views

Can one ping a NIC by MAC

I have an NIC card on a Debian machine somewhere. The machine is turned off, but I need to know whether the NIC card is turned on so that I can send a wake-on-lan magic packet later (from another ...
6
votes
1answer
313 views

Why the difference between network addresses reported by hostname and ping?

I have tried hostname and ping in a cluster machine, with different outputs. I am wondering what is the difference between the two? For example, on the same machine, hostname outputs node4.XXX and ...
6
votes
3answers
7k views

What prevents a machine from responding to pings?

I have a CentOS release 5.4 linux box on Amazon EC2 that I'm trying to set up to be monitored via Nagios. The machine is in the same security group as the nagios server, but it seems to be ...
5
votes
1answer
305 views

root owned program with setuid bit on

Ping is a a program owned by root with the user id bit set. $ ls -l `which ping` -rwsr-xr-x 1 root root 35752 Nov 4 2011 /bin/ping As I understand it, if a user runs the ping process, then the ...
5
votes
3answers
7k views

How does traceroute resolve names?

While writing a script, I wanted to reference a machine by the computer name that I gave it (e.g. "selenium-rc"). I could not ping it using "selenium-rc", so I tried the following commands to see if ...
4
votes
3answers
5k views

How can i check that a remote computer is online for ssh / script acess?

i'm writting a script that will backup data from my laptop to an ubuntu server. to do so, i'm looking for a (ba)sh command to test if the server is available before starting the backup. something like ...
4
votes
4answers
2k views

“internet connection checker one-liner”

With this I can check, that there is "internet connection". if there is no "internet connection" (succesfull pings to this 2 places), then it waits 600 sec, then it runs along: ping -W 1 -c 4 ...
4
votes
2answers
2k views

Can't ping broadcast

We're running four computers connected to a hub (yes a hub not a switch) on Fedora 13. They were installed using images from a colleague that has recently left us to go back to school, they may have ...
4
votes
2answers
354 views

My Ping command does not seem to ever finish. Does that mean it is suceeeding?

I am pinging a remote IP. I know very little about the Ping command. When I ping the IP, it keeps going and going... I am not using the -t option. Me$ ping 137.30.124.104 PING 137.30.124.104 ...
4
votes
1answer
153 views

Strange ping behavior

I built a linux distribution using the Yocto Project, with little customization. It runs on a Single Board Computer. When I ping this machine, I get the following result: PING 10.128.11.1 ...
3
votes
3answers
130 views

SSH to two addresses, use the one that connects first

I have a home computer (let’s call it franklin because that’s what I call it) that I often ssh into from my work laptop. When I’m at home, I ssh to franklin.local, and when I’m at work or anywhere ...
3
votes
3answers
94 views

Is there some way I can start a (repeating) ping while the network is unreachable?

My ping command (on Debian 6 or 7) will repeatedly attempt to ping a server even while the network is down, if the network was up when it was started. Is there some way to start ping while the network ...
3
votes
1answer
73 views

Check ping statistics without stopping

Is there a way to tell ping to show its usual termination statistics without stopping the execution? For instance, I'd like to quickly view: --- 8.8.8.8 ping statistics --- 2410 packets transmitted, ...
3
votes
1answer
4k views

Cannot reach outside network or IP after upgrading to Ubuntu 12.04

I am running Ubuntu 12.04 on my server but since the upgrade from 10.04 I can no longer reach any outside sources of the server. I can SSH into the box, but from inside here I can not reach anything. ...
3
votes
1answer
855 views

Very slow response from localhost when pinging

Networking is working fine on my gentoo machine. One connection is made, everything works fine with normal speed. But it is slow to wake-up : starting up connection is taking time. Even pinging ...
3
votes
2answers
22k views

Host unreachable and I do not get why

I can not open a specific website. This is a website hosted by our company, and I know it is up. However, these are my symptoms: VARIABLES: host.com - the website I can not open x.x.x.x - the IP of ...
3
votes
2answers
1k views

ping -c1, wait for all responses from broadcast

I want to send one packet to the broadcast address, but wait for all responses. If I do ping -c 1 192.168.1.255, it sends just one packet, but it quits after getting the first response.
3
votes
1answer
55 views

Did this tutorial block pings to my server?

I am a programmer teaching myself linux admin stuff. I followed this tutorial to setup a firewall on a VPS. As a part of that tutorial, I block all traffic except for web traffic and SSH traffic. I ...
3
votes
1answer
999 views

LAN server with two network cards, can't telnet / ping to the second even if it works

I have an issue with an Ubuntu 12.04 LTS (updated) server. For reasons too long to detail, it has got one eth0 interface assigned to 192.168.1.9 and one Wifi wlan0 interface assigned to 192.168.1.10. ...
3
votes
2answers
2k views

Problem pinging from a specific interface

I'm trying to ping from a specific interface, I have a wired and a wireless connection both going into my laptop. My wired adaptor eth0 is on the IP 172.16.109.75 My wifi adaptor wlan0 is on the IP ...
3
votes
1answer
2k views

qemu - two clients (tap0 & tap1) via br0 can't ping eachother but server pings ok

I've got: A host system running Ubuntu with KVM (functional) Two clients, one Ubuntu and one Windows 7, nothing fancy. I've also setup (see below) a bridge via br0 for the clients: br0: ...
2
votes
2answers
10k views

Cannot connect to my Virtual Box Ubuntu system

I have a VirtualBox running an Ubuntu OS. I'd like to access this Ubuntu machine using ssh or telnet. In order to do that I've performed the following steps: sudo apt-get install telnetd sudo ...
2
votes
1answer
276 views

Constantly pinging a server

I am not sure if this is exactly the right place for this question, but there is no networking stack exchange. I want to ping a server a bunch of times (eg.10,000+) to gather information on the ...
2
votes
2answers
287 views

ssh reverse tunneling not working

So, I have a server and a home machine. My server can't talk to internet, but my home machine can. So, I set up a reverse tunnel through home to server using: ssh -R 9001:www.google.com:80 server ...
2
votes
2answers
719 views

Behavior of ping with partial packet loss on Ubuntu

I am specifically looking on the return variables of running ping on my Ubuntu server, the variables I am looking for is: error status, output on stdout, output on stderr. When pinging a host the ...
2
votes
1answer
2k views

Ubuntu server cannot access the Internet: appears DNS related

This is a Drupal website running Ubuntu 12.04 LTS on Linode. The server is just a website. It is not a DNS server or anything else. Here are my issues. It seems they are all related to DNS issues. ...
2
votes
1answer
89 views

Most reliable way to check for connected client?

I have an embedded Linux OS developed from scratch using Yocto. This talks to a Windows XP/7 client. The embedded OS runs a DHCP server and gives an address to the client. The problem is that the ...
2
votes
1answer
76 views

How do I create an IPv6 overlay network?

I would like to create host-only IPv6 networks on two hosts and then route between them. On each host, there will be a dummy interface, at ipv6_prefix::9. I would like to be able to ping that ...
2
votes
3answers
2k views

Why can't I ping Google?

I can't ping google.com (unknown host). But I can ping IP addresses. I tried to ping the IP address of Google but it doesn't work. resolv.conf nameserver 8.8.8.8 nameserver 209.139.209.33 ...
2
votes
1answer
252 views

Suppress “Alarm clock: 14” from ping

I've made a simple script for rebooting my router and afterwards showing a progress bar until my computer has an internet connection again. When running the script I get the following output: The ...
2
votes
1answer
10k views

Unable to ping gateway & other Linux boxes on same network

I'm somewhat new to Linux, but I'm trying to network a few Linux machines. I can't seem to be able ping the gateway or the other Linux machines. My scenario: I have a few Linux boxes set up on a ...
2
votes
1answer
585 views

How to check if apt proxy configuration is correct?

I have to use a proxy server which requires authentication. So, I need to update the apt.conf file to include my proxy settings. All fine. What I need is to check that the configuration is correct so ...
2
votes
3answers
842 views

Send Email without any settings fast?

I am looking something like this on dummy comp, sending email fast without any login. I mean that I do not want to set up any .muttrc or any other settings. I want just a short msg to person A from ...
2
votes
1answer
380 views

Redhat Enterprise Linux 4.7 - Ping problem

When I try to ping some of the IP addresses I get "connect: No buffer space is available" error. Also when I check /var/log/messages, there are some errors like as following printk: 99 messages ...
2
votes
0answers
65 views

Ping command results in packet loss

Whenever I ping on my personal computer, nothing gets displayed other than a single statement. Upon stopping execution, I see that several packets were transmitted in the statistics. On top of all ...
2
votes
1answer
671 views

Quickly check whether many network hosts are up-and-running

Objective: check if a host is up-and-running on the network, with a method that can be efficiently parallelized over many hosts. Emphasis on a QUICK turnaround of the check. Reason to emphasise ...
2
votes
0answers
418 views

Network via ieee1394 is unreachable (PC and laptop)

I decided to connect my PC to the laptop via firewire. All interfaces are up, but no packets can be send/recieved. I'm using Linux Slackware64-current (kernel 2.6.37.4) Laptop (Dell Vostro 3700) has ...
1
vote
2answers
3k views

What is a valid hostname label?

I set up my hostname to a number, where running hostname gives: 6592 But when I run ping 6592, I get: connect: Invalid argument I checked the related Wikipedia page, and it does say that such a ...
1
vote
2answers
9k views

Changing the IP Address in Solaris 11

I am trying to change the IP address in Solaris, but am failing to do so. The IP address needs to be a fixed number, like 10.0.11.10 I have tried changing the IP address in /etc/hosts which I ...
1
vote
2answers
1k views

Why doesn't “ping -l” works when ping works?

Bye all, ping AddressIp 64 bytes from indirizzoIp: icmp_req=1 ttl=42 time=149 ms while if ping AddressIp -l 1400 ping: cannot set preload to value > 3 ping AddressIp -t -l 1400 ping: can't ...
1
vote
1answer
357 views

Command-line way of send pinging

I have lots of Drupal powered website. Each of the website has Multiping module to pinging ping server. Is there any way of send pinging through command-line? I hope I can build dedicated server for ...
1
vote
2answers
59 views

What could cause a ping request to return inconsistently timed results

Here is a sample run: 64 bytes from 192.168.1.9: icmp_seq=27 ttl=64 time=8852.917 ms 64 bytes from 192.168.1.9: icmp_seq=28 ttl=64 time=7918.074 ms 64 bytes from 192.168.1.9: icmp_seq=29 ttl=64 ...
1
vote
2answers
2k views

How to check whether certain port is opened or block on any other servers from a dev box?

I am trying to connect to one of our staging Cassandra servers on port 9042 and 9160 here in our company from a dev box.. Through the code, I am not able to connect to it... The program gets hanged at ...
1
vote
1answer
145 views

Ping from Outside: How do I make my system invisible?

I just did a test that told me my gateway (debian squeeze) responds when being pinged from outside. It's a box with two network cards, eth0 is for my internal network (192.168.1.0/24) and eth1 goes ...
1
vote
2answers
229 views

How to make dns resolve faster

I changed name server of one domain. Then I flush dns root@host [~]# /etc/init.d/named restart Stopping named: [ OK ] Starting named: ...
1
vote
2answers
302 views

need portable crontab host-checking/failover logic across Linux & Cygwin

A host-ping test that always works correctly from the interactive bash command line in Cygwin, is behaving incorrectly in its own crontab--always selecting the second host--and I can't figure out why: ...
1
vote
1answer
64 views

Using ping on multiple interfaces on a NIC

I have two systems and each have a NIC with two ethernet ports. One system has a verified NIC card, but the other has a NIC which has to be verified. I use ping to verify whether the interfaces on ...