Network analysis tablets — full-suite devices that automate security, networking, and application monitoring — are a welcome addition to the toolkit that network and security engineers use to assess infrastructure health and application performance. All-in-one testers from companies like Fluke and AirMagnet remain the Ferraris of network analysis and troubleshooting. These are brilliant but out of reach for the budget-lean datacenter admin and organization. Today, with a $100 investment in a basic Android tablet and a few apps, you may be able to add enough mobility to your analysis operation to get by.
Here are three of my favorites.
Fing network utility
Fing is an Android implementation of the Look@LAN freeware product for Windows OS, Linux, or Mac OS. It performs network discovery on IP networks you configure, and it will display the NetBIOS or DNS name, MAC address, and vendor (not a full OS version detect). Select any individual IP address, and you can ping, traceroute, or query the DNS name of the host or do a service scan (full or partial listening port enumeration). You can save scans to SD. If you subscribe to the Fingbox cloud service, you can automate TCP service monitoring, receive discovery or alert notifications, or remotely reboot hosts via Sentinels you install on networks you monitor.
You can find hundreds of WiFi scanners on app stores. WiFi Analyzer views offer pretty much all you need from a scanner. You can scan signal strength automatically or by intervals, identify the optimal channel to use for a given access point (AP), and enumerate APs. One graphing function displays the signal strength of all APs over time. A second visualizes APs by signal strength and channel. You can configure the app to display APs that share the same SSID and security individually or as a group, set aliases for discovered APs, and display full security settings. It's fancy, fast, and free.
UltraTools provides a collection of network analysis, performance, and diagnostic tools and more. The app has so many utilities it comes with a dashboard. For network analysis purposes, the port scanner, visual traceroute, DNS lookup, and ping complement Fing nicely.
For network or performance engineering purposes, UltraTools provides a connection speed test, a DNS speed test, and an IPv6 connectivity test. You can also run a terrific set of checks against your domain with Domain Health Report, one of the utilities you can access from the UltraTools dashboard.
The Domain Health Report scans include a DNS record validity check of authoritative zone data, name server(s) configuration, and DNSSEC and IPv6 support for name service (AAAA resource records). The scanner drills down through the targeted zone's resource records, performs MX record validity and consistency checks, and connects to each mail server enumerated to assess whether its responses conform to best-practices. The scanner also performs validity checks on each web server enumerated in the authoritative zone.
The information in the Domain Health Report provides security engineers with data you don't typically find in other utilities. The scan reports on mail server health and behaviors (returns valid banners, responds to ports 25/587, has SPF records, responds to abuse@domain email) and tells you whether the mail server is on the real-time block list (RBL). It also reports on web server behaviors (has public IPs, IPs have reverse DNS entries, has CNAME records). You can also query web servers for server software version, home page HTTP headers, META tags and load time, and SSL certificate validation.
This app can also be a powerful investigation tool when run against a domain you suspect is malicious (e.g., a suspected phishing site or spam relay). The scans will often reveal misconfigurations commonly found on servers run by attackers. You can investigate further by querying the Whois or the RBL, or you can geolocate the suspicious server through the UltraTools dashboard. This freeware app is about as comprehensive a utility as you'll find.
The apps I've recommended are available via Google Play, the Amazon App store, or directly from the developer. None require you to root your tablet. I first installed these on a Android tablet I bought for less than $100, and I had had no issues. A small investment of this kind may reap benefits orders of magnitude larger.
Update 21 October 2013
I've since upgraded to a Nexus 7 running Android 4.3. The scans run faster, the tablet is much sturdier, and the display is brilliant. Here's some further research since I originally posted this column?
What, no nmap? I could not find an app by Fyodor and the rest seemed iffy or had numerous complaints of lack of support.
What about packet capture? There are few choices if you don't want to root your device. tPacket Capture uses the Android Vpnservice and saves captured traffic in pcap format. Upload the file(s) to a system and further analyze these using Wireshark. If you're willing to root your device, try bitShark. I've yet to try Android PCAP Capture: this app avoids rooting your device by capturing from an external (USB) WiFi adapter that uses the RDL 8187 chipset. Check the developer site for compatible adapters and Android devices if this sounds interesting.
What about intrusion detection. There are few apps that do more than detect minimum, suspicious activity on the local WiFi network. I was disappointed with Intrusion Detector, which enumerates MAC and IP addresses of hosts on your network, asks you to name "authorized" hosts, and remembers these bindings. If you've installed Fing, you have this capability.
Originally posted 15 July 2013 at The Transformed Data Center.
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