You can’t pass it as the argument to call() because the method signature doesn’t allow it. However, you can pass the necessary information as a constructor argument; e.g. public class DoPing implements Callable<String>{ private final String ipToPing; public DoPing(String ipToPing) { this.ipToPing = ipToPing; } public String call() throws SomeException { InetAddress ipAddress = InetAddress.getByName(ipToPing); … Read more
The question was to see if ping responded which this script does. However this will not work if you get the Host Unreachable message as this returns ERRORLEVEL 0 and passes the check for Received = 1 used in this script, returning Link is UP from the script. Host Unreachable occurs when ping was delivered … Read more
You should use nmap: nmap -T5 -sn 192.168.0.0-255 nmap -T insane -sn 192.168.0.0-255 # same as above but w/named template The -T 5/insane option uses the “insane” template, which: insane mode assumes that you are on an extraordinarily fast network or are willing to sacrifice some accuracy for speed. -T4 (aggressive) prohibits the dynamic scan … Read more
Not all machines have nmap available, but it’s a wonderful tool for any network discovery, and certainly better than iterating through independent ping commands. $ nmap -n -sP 10.0.0.0/24 Starting Nmap 4.20 ( http://insecure.org ) at 2009-02-02 07:41 CST Host 10.0.0.1 appears to be up. Host 10.0.0.10 appears to be up. Host 10.0.0.104 appears to … Read more
In most cases simply switching the virtual machine network adapter to bridged mode is enough to make the guest machine accessible from outside. Sometimes it’s possible for the guest machine to not automatically receive an IP which matches the host’s IP range after switching to bridged mode (even after rebooting the guest machine). This is … Read more
You should redirect stderr to stdout. To do that, change your exec() call like this: exec(“ping -c 1 $domain_bad 2>&1”, $output, $return_var); More info about 2>&1 meaning here.
I’ve faced the exactly same problem but I’ve fixed it with another approache. Using Ubuntu 18.04, first disable systemd-resolved service. sudo systemctl disable systemd-resolved.service Stop the service sudo systemctl stop systemd-resolved.service Then, remove the link to /run/systemd/resolve/stub-resolv.conf in /etc/resolv.conf sudo rm /etc/resolv.conf Add a manually created resolv.conf in /etc/ sudo vim /etc/resolv.conf Add your prefered … Read more
InetAddress.isReachable() according to javadoc: “.. A typical implementation will use ICMP ECHO REQUESTs if the privilege can be obtained, otherwise it will try to establish a TCP connection on port 7 (Echo) of the destination host..”. Option #1 (ICMP) usually requires administrative (root) rights.
See this pure Python ping by Matthew Dixon Cowles and Jens Diemer. Also, remember that Python requires root to spawn ICMP (i.e. ping) sockets in linux. import ping, socket try: ping.verbose_ping(‘www.google.com’, count=3) delay = ping.Ping(‘www.wikipedia.org’, timeout=2000).do() except socket.error, e: print “Ping Error:”, e The source code itself is easy to read, see the implementations of … Read more
Ping returns different exit codes depending on the type of error. ping 256.256.256.256 ; echo $? # 68 ping -c 1 127.0.0.1 ; echo $? # 0 ping -c 1 192.168.1.5 ; echo $? # 2 0 means host reachable 2 means unreachable