Condition to test if a host can be pinged Post: 302622189

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Top Forums UNIX for Advanced & Expert Users Condition to test if a host can be pinged Post 302622189 by MaindotC on Wednesday 11th of April 2012 05:16:46 PM

04-11-2012

Registered User

Condition to test if a host can be pinged

I have a much larger script that takes an input file of hosts and determines if we support them and checks to ensure the FQDN coincides with our DNS. For instance, the hostname may return a different FQDN when passed to the "host" command, so I keep the value of the output of the "host" command and also apply some conditions to determine if NXDOMAIN is returned.

In a stunning twist of fate I see that sometimes the file I'm reading returns the ip address of a machine with more than one NIC (and ip address), and usually that NIC is not in operation so it's screwing up my reporting. I need to put a condition in my script that not only checks to see if the ip returns a valid hostname using the "host" command, but now I also need to the script to ping the machine and ensure it is working.

The input file contains a hostname, and three fields following the hostname. Each field is reserved for an IP address - sometimes there's 1 ip, sometimes 2, or 3. I already have a test to determine if the ip address works:

Code:

# if tmp1 is not a zero value
        if [[ -n $tmp1 ]]
        then

# if hosting the value of tmp1 does not return NXDOMAIN (hence if it's a valid host)
# and if that host can be pinged
# then host that value and exit the loop
                if [[ -z `host $tmp1 | grep -o NXDOMAIN` ]]
                then
                        host $tmp1 | cut -d" " -f5 | sed 's/.$//g'
                else
                        if [[ -n $tmp2 ]]
                        then
                                if [[ -z `host $tmp2 | grep -o NXDOMAIN` ]]                                then
                                        host $tmp2 | cut -d" " -f5 | sed 's/.$//g'
                                else
                                        if [[ -z `host $tmp3 | grep -o NXDOMAIN` ]]
                                        then
                                                host $tmp3 | cut -d" " -f5 | sed 's/.$//g'
                                        fi
                                fi
                        fi
                fi
        else echo $i >> exceptions_$dt
        fi
done

This works fine as is. However now I need to add an additional condition that says "can the host be pinged also? If not exit the loop and move onto the next one". I tried to add this but it's somehow sending an invalid value to the host command:

Code:

if [[ -z `host $tmp1 | grep -o NXDOMAIN` && -n `ping -c 1 -w 1 $tmp1` ]]

I tried putting the ping condition in its own brackets separating the conditions by the ampersands but I'm still having a problem. Can anyone suggest how I can implement this additional check?

MaindotC

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LEARN ABOUT LINUX

ftpaddhost

ftpaddhost(1M)                                            System Administration Commands                                            ftpaddhost(1M)

NAME

       ftpaddhost - set up a virtual FTP host

SYNOPSIS

       ftpaddhost -c | -l [-b] [-x xferlog] hostname root_dir

DESCRIPTION

       The  ftpaddhost  script is executed by the super user to set up virtual FTP hosts. The ftpaddhost command configures the virtual host host-
       name under directory root_dir. The value of hostname can be an IP address or the name of a host.

OPTIONS

       The ftpaddhost script supports the following options:

       -b                      Create a banner for the virtual host. This option is useful to confirm that the virtual host is working.

       -c                      Configure complete virtual hosting. This option allows each virtual host to have its own version of the  ftpaccess,
                               ftpconversions, ftpgroups, ftphosts, and ftpusers files. The master version of each of these configuration files is
                               copied from  the  /etc/ftpd  directory  and  placed  in   the  /etc/ftpd/virtual-ftpd/hostname  directory.  If  the
                               /etc/ftpusers file exists it is appended to the virtual ftpusers file. If a virtual host lacks its own version of a
                               configuration file, the master version is used.

       -l                      Configure limited virtual hosting. This  option allows a small number of parameters to  be  configured  differently
                               for a  virtual host. See the virtual keyword on the ftpaccess(4) manual page.

       -x xferlog              Create a logfile entry such that the transfer logs for the virtual host are written to the specified file. An abso-
                               lute path must be specified for the xferlog file.

OPERANDS

       The following operands are supported:

       hostname        The host name or IP address of the virtual server.

       root_dir        The absolute pathname of the directory under which the virtual server is set up.

EXIT STATUS

       The following exit values are returned:

       0        Successful completion

       1        Improper usage of the command

       2        Command failed

FILES

       /etc/ftpd/virtual-ftpd/hostname         The configuration files directory for the virtual host hostname.

ATTRIBUTES

       See attributes(5)  for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWftpu                     |
       +-----------------------------+-----------------------------+
       |Interface Stability          |Evolving                     |
       +-----------------------------+-----------------------------+

SEE ALSO

       ftpconfig(1M), in.ftpd(1M), ftpaccess(4), ftpconversions(4), ftpgroups(4), ftphosts(4), ftpusers(4), xferlog(4), attributes(5)

SunOS 5.10                                                          1 May 2003                                                      ftpaddhost(1M)

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