Automated tools can be quite harmful to production environments. Exercise care, and design the test in a manner that will not affect production systems.
These tools can be quite helpful and guide you toward parts of your configuration file that might need further review. A strong case could be made that new configuration files should be tested with good peer reviews and tools such as those listed below. Many general vulnerability scanners also test commonly exploited vulnerabilities for networking platforms.
Router Audit Tool (RAT): http://www.cisecurity.org
Wireshark (formally Ethereal): http://www.wireshark.org
TeraTerm Pro: http://www.hp.vector.co.jp/authors/VA002416/teraterm.html
Top 100 Security Tools: http://www.sectools.org