Simple Tcl Script Ping Test

You can use a simple Tcl script to test connectivity between your devices:

foreach address {
x.x.x.x
x.x.x.x
x.x.x.x} { ping $address
}

For example:

R1#tclsh
R1(tcl)#foreach address {
+>(tcl)#172.12.23.2
+>(tcl)#172.12.23.3
+>(tcl)#172.12.23.4
+>(tcl)#172.12.23.6
+>(tcl)#172.12.23.7
+>(tcl)#} { ping $address re 10 si 1500
+>(tcl)#}

Type escape sequence to abort.
Sending 10, 1500-byte ICMP Echos to 172.12.23.2, timeout is 2 seconds:
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 4/4/4 ms
Type escape sequence to abort.
Sending 10, 1500-byte ICMP Echos to 172.12.23.3, timeout is 2 seconds:
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 4/4/4 ms
Type escape sequence to abort.
Sending 10, 1500-byte ICMP Echos to 172.12.23.4, timeout is 2 seconds:
……….
Success rate is 0 percent (0/10)
Type escape sequence to abort.
Sending 10, 1500-byte ICMP Echos to 172.12.23.6, timeout is 2 seconds:
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 1/1/4 ms
Type escape sequence to abort.
Sending 10, 1500-byte ICMP Echos to 172.12.23.7, timeout is 2 seconds:
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 1/3/4 ms
R1(tcl)#tclquit
R1#

Type “tclsh” to enter the Tcl shell.  You can see that you can add extended commands to the ping command (repeat 10 size 1500 in this case).  I included IP address 172.12.23.4 to show the output when a ping is not successful. 

Be sure to type “tclquit” after the script has run.  Usually you will see the “(tcl)” at the command prompt, but I have seen that disappear even though you are STILL in the Tcl shell.  This has happened to me when I go into config mode from Tcl shell.  After [cntrl + z] I exit out to the command prompt, but the “(tcl)” does not show:

r1#tclsh
r1(tcl)#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
r1(config)#^Z
r1# <- still in Tcl shell!!!

I generally keep a copy of the Tcl script in a text file so that I can just paste it into the router to test connectivity at any time.  The extra time it takes to create/modify the text file is much less than the time it would take to type “ping x.x.x.x” for each device.  You are also less likely to forget a device.

Command Reference

Cisco IOS Scripting with Tcl

TCL’ing Your Cisco Router