Linux test internet connection code#
Linux test internet connection free#

Hash play 2>&- || 'Ĭreate a script in the /etc/init.d folder with the following content (I called it testcond) #echo Computer starting or testing daemon initĭate | mail -s 'Server is up and Internet is online' Įcho 'Internet was found down $current_time' > /mnt/data/Server/internet_log.txt Since my Internet connection is unstable I created this script ( based on this one) that makes a gentle chord sound to call me, and also uses Ubuntu notify when the Internet connection comes back: #!/bin/bash

Something similar occurs with DNS if you test with an IP. ping is ICMP, so it might work even if the web proxy is down. However, this is not telling whether you really have connectivity or not, just whether cable is connected and something is on other end.Ĭhecking whether Internet is working is not so trivial. If you want to check cable state, you can use sudo ethtool eth0 If so, you may get ping responses and non-error HTTP status codes, even when you can't access any other sites. You may encounter problems with some public wifis when there is a login gateway that redirects all pings and HTTP requests. Parameter -c1 is limiting number of ping packets to one.

Linux test internet connection code#

You can automatically check return code by using variable $?. You can for example run ping -c1 on multiple well known sites (for example and ) and check return codes to determine whether any destination is reachable. There isn't really easy way to handle this in every case. That will return error if DNS server is not responding, even if OpenDNS or your own provider's DNS server works fine. You can write short workaround with host, for example host. If your provider has cached your DNS record, but the DNS server is down, others can't access your site even though monitoring says everything is fine. Yet again, there are shortcomings in this approach. Checking the return code is straightforward way to do implement this: wget -spider -quiet Įcho 'Website failed!' | mail -s 'Website down' You'll get some false positives when your computer is down, or when your DNS server is not working. Second, using wget -spider for your own script is a good idea. (Disclaimer: I am not affiliated with Pingdom in any way).

Linux test internet connection free#

To pick one, Pingdom includes free account for monitoring one target. What do you think?įirst, multiple good online monitoring services are available. Also (I was trying to avoid any I/O) I can write to a log file by which I can check the count of downtime checks and then skip further checks till the site is down or cause longer checks (10mins instead of every min). Right? Also how can I randomize pinging to a different site everytime, like facebook, google, yahoo etc. Its a bit heavy (as I am not using ping) but should not give any false positives. This way I need to check for internet connectivity only where there is an issue with my blog response code. # Check if we have internet connectivity by some other siteįLAG=1 # This means we do have internet connectivity and the blog is actually downĭISPLAY=:0 notify-send -t 2000 -i /home/ashfame/Dropbox/Ubuntu/icons/network-idle.png 'Downtime Alert!' ' is down.' # A good point is to check if the internet is working or not # Traverse the string considering it as an array of words

# Sending the output of the wget in a variable and not what wget fetches Here is my script to keep checking downtime for my blog: #!/bin/bash So, checking for DNS and LAN connectivity is a bit overkill for me as I don't have that much specific need to figure out what problem it is.

Now I want to make sure that it displays me notification when I do have internet connectivity. So I keep on getting notifications as the script couldn't find 200 in the wget response. LAN was connected fine but just I couldn't access any site. Now yesterday, there was some problem with my Internet. If its not 200, it notifies me (I believe this will be better than just pinging it, as the site may under be heavy load and may be timing out or respond very late). I have setup cron to check it every minute.įor this, I am checking the HTTP response code of wget -spider to my blog. My intention at the moment is to check if my blog is down. But I think there must be easy way without the need of checking a site that never crash )Įdit: Seems like there can be a lot of factors which can be individually examined, good thing. One idea I seem is to wget -spider and check the HTTP response code to interpret if the Internet connection is working fine. Is there an easy way to check Internet connectivity from console? I am trying to play around in a shell script.