Tclsh implementation of host

Jason Pfeifer · ‎10-28-2011

osted By:	jclarke
Posted Date:	Jul 11, 2008
Category:	Network Management
Version:	1.0
License:	Cisco-Style BSD
Summary:	Tclsh script to do DNS lookups on IOS.
Script Modified Date:	Jul 11, 2008
Cisco IOS Version tested:	12.4T
Cisco Products Tested:	7206
Environment Variables used:
Rating Count:	0
Average Rating:	0
File Size:	3 KB
Script Info URL:

This tclsh script implements the UNIX host command on IOS. The host.tcl script is currently limited to IPv4 A and PTR lookups only. It can also dynamically determine the DNS server by looking at the running config. However, if you want to specify a DNS server to use, that is also possible. To use the script, do the following: tclsh host.tcl HOST [DNS SERVER] Where HOST is the hostname or IP address to lookup, and DNS SERVER is an optional DNS server name or IP address. For example: Router#tclsh flash:host.tcl www.cisco.com www.cisco.com has address 198.133.219.25 Router#tclsh flash:host.tcl 198.133.219.25 10.1.1.1 25.219.133.198.in-addr.arpa domain name pointer www.cisco.com

chris.moody · ‎12-08-2013

I could use some help trying to figure out why this utility doesn't output anything on either of the Cisco devices I try it from. If I execute this utility from say, a linux host, and it executes properly and returns a valid lookup.

I run it from a 2621 and only get back an empty line as a result. I run it from a 2811 and only get back the string 'ERROR' followed by an empty line.

any thoughts as to how to debug further to determine what in IOS is preventing this from working?

-Chris

Joe Clarke · ‎12-08-2013

There is a newer version of this script at https://supportforums.cisco.com/docs/DOC-19590 that might help. Else, what version of code are you running on these devices? Do you use command authorization?