Running root level networking commands from a script

English Programming/Scripting
1

So I am both new to Linux and bash scripting and am attempting to make a script that checks network settings and connectivity in a new bash shell window when a non-root user logs on.
Currently I am running into an issue where the script will run but have errors if I do not run the script as root. I know this means I have a permissions issue and am trying to figure out the minimum required permissions to run the script without error.
Setting the SUID does not resolve the issue.
Thanks in advance for looking at this.

Below is the ls -l
-rwsr-xr-x 1 root root 1367 Jan 17 08:46 ifscript.sh*

**Here is the output of the script when run as a normal user. **
mark@linux-ika4:~/bin> ifscript.sh
VERIFYING NETWORKING SERVICE
Network Service: ON
/home/mark/bin/ifscript.sh: line 13: route: command not found

TESTING LOCAL IP CONNECTIVITY
Usage: ping -LRUbdfnqrvVaAD] -c count] -i interval] -w deadline]
-p pattern] -s packetsize] -t ttl] -I interface]
-M pmtudisc-hint] -m mark] -S sndbuf]
-T tstamp-options] -Q tos] [hop1 …] destination
Ping Error

TESTING REMOTE IP CONNECTIVITY
IP=SUCCESS

TESTING DNS AVAILABILITY
DNS=REACHABLE

TESTING DNS - RESOLVING WWW.MSN.COM
Address: 131.253.13.140

DISPLAYING NETWORK INFO
Default Gateway:
Primary DNS: 172.25.80.20
/home/mark/bin/ifscript.sh: line 56: ifconfig: command not found
Interface: eth0
/home/mark/bin/ifscript.sh: line 63: ifconfig: command not found
mark@linux-ika4:~/bin> ifconfig
Absolute path to ‘ifconfig’ is ‘/sbin/ifconfig’, so running it may require superuser privileges (eg. root).

Here is the output when run as root.
linux-ika4:/home/mark/bin # ifscript.sh
VERIFYING NETWORKING SERVICE
Network Service: ON

TESTING LOCAL IP CONNECTIVITY
IP=SUCCESS

TESTING REMOTE IP CONNECTIVITY
IP=SUCCESS

TESTING DNS AVAILABILITY
DNS=REACHABLE

TESTING DNS - RESOLVING WWW.MSN.COM
Address: 131.253.13.140

DISPLAYING NETWORK INFO
Default Gateway: 10.0.2.2
Primary DNS: 172.25.80.20
Interface: enp0s3
inet addr:10.0.2.15 Bcast:10.0.2.255 Mask:255.255.255.0
**
Here is the script.**
#!/bin/bash
#runs networking test commands
echo VERIFYING NETWORKING SERVICE
CHKCFG=$(chkconfig network)
case $CHKCFG in
‘network on’) echo Network Service: ON
;;
‘network off’) echo Network Service: OFF
;;
*) echo No response to chkconfig network
;;
esac
DG=$(route | head -n 3 | tail -n 1 | cut -d ’ ’ -f10)
echo
echo TESTING LOCAL IP CONNECTIVITY
ONE=$(ping $DG -c 1 | grep packets | cut -d ’ ’ -f 4)
case $ONE in

  1. echo “IP=SUCCESS”
    ;;
  2. echo “IP=FAILED”
    ;;
    *) echo “Ping Error”
    ;;
    esac
    echo
    echo TESTING REMOTE IP CONNECTIVITY
    ONE=$(ping 8.8.8.8 -c 1 | grep packets | cut -d ’ ’ -f 4)
    case $ONE in
  3. echo “IP=SUCCESS”
    ;;
  4. echo “IP=FAILED”
    ;;
    *) echo “Ping Error”
    ;;
    esac
    echo
    echo TESTING DNS AVAILABILITY
    DNS=$(cat /etc/resolv.conf | grep nameserver | head -n 1 | cut -d ’ ’ -f2)
    ONE=$(ping $DNS -c 1 | grep packets | cut -d ’ ’ -f 4)
    case $ONE in
  5. echo “DNS=REACHABLE”
    ;;
  6. echo “DNS=FAILED”
    ;;
    *) echo “Ping Error”
    ;;
    esac
    echo
    echo TESTING DNS - RESOLVING WWW.MSN.COM
    nslookup www.msn.com $DNS | grep Address:| tail -n 1
    echo

echo DISPLAYING NETWORK INFO
echo Default Gateway: $DG
echo Primary DNS: $DNS
INTER=$(ifconfig | grep enp0s3)
if -n “$INTER” ];
then
echo “Interface: enp0s3”
ifconfig enp0s3 | grep "inet "
else
echo “Interface: eth0”
ifconfig eth0 | grep "inet "
fi

exit 0
**
—end of script—**

2

ifconfig and route are located in /sbin/ which is not in the user’s path by default.
Just call them with the full path name, i.e. replace all occurences of “ifconfig” with “/sbin/ifconfig” and “route” with “/sbin/route” in your script.

AFAICS your script should run then with user permissions.

3

Here we go again :frowning: (not your fault, it is hidden somewhere).

Please use CODE tags around your copied/pasted computer texts. You get the CODE tgas by clicking on the # button in the tool bar of the post editor. And please copy prompt, command, output, next prompt all in one sweep (you partly did that already), The no explantions like “Below is the ls -l” is needed, because it ius already there.

4

Better yet, use the shoter, easier, consolidated commands that weren’t
deprecated a decade ago (from the ifconfig manpage: “WARNING: Ifconfig is
obsolete on system with Linux kernel newer than 2.0. On this system you
should use ip. See the ip manual page for details”):

Code:

ip addr
ip route

No more need for the full path, shorter typing, ongoing development, can
type ‘ip’ with one hand… all good things.

–
Good luck.

If you find this post helpful and are logged into the web interface,
show your appreciation and click on the star below…

5

Thanks all!
I managed to get it working and am now digging through the ip man page.
I will use the

tags in the future and didn’t know they existed. Neat feature…

6

That is not your fault. It is rather hidden. Thus we have to explain to every one again and again :frowning: