One of those essential tools every sysadmin should have to hand
Rating: 10 out of 10
IncentivizedUse Cases and Deployment Scope
Nmap is one of those long-standing tools that everyone turns to when they need to scan a network for devices, services, open ports, etc. In our company, it gets used regularly for troubleshooting, auditing, and general tinkering. I'm not sure what we would use in place of it, because there's never been a reason to look elsewhere. It's been around since the 90's and it's always to hand!
Pros
- Comprehensive port scanning of both TCP and UDP ports.
- Clever 'interrogation' of services listening on open ports. It will use all sorts of techniques to try and work out what service is listening on a port, and potentially even version and host information, etc.
- Very configurable. You can choose exactly what you want to scan for, limit to port ranges, protocols, IPs, etc.
- Very scriptable. Being a command-line utility (check out Zenmap if you want a GUI), you can call it from your own scripts, automation pipelines, etc.
Cons
- Not a problem with Nmap, per se, but the related Zenmap GUI could do with some love! It does the job perfectly well so I shouldn't complain, but it would benefit from a modern makeover.
Likelihood to Recommend
If you're a sysadmin, or anyone who's had to deploy network services, you've almost certainly had to use Nmap at some point or other. Need to see what devices are on your LAN? Nmap can tell you that. Want to check which ports your web server has open to the internet? Nmap is your friend.
Nmap is a powerful command-line tool and has many options that require some reading of documentation to get the best out of (although generally straightforward). If the thought of working at the command-line scares you (presumably not if you're reading this review), then you may want a much simpler tool, or at least check out Zenmap GUI.
Vetted Review
15 years of experience