Zenmap Mac fails across IPSec VPN

[cybernorris]

After an full uninstall and new clean install of nmap 7.12, Zenmap is finally running on my Mac Mini (OSX 10.11.4). I'm now running into an issue of Zenmap not working through a VPN connection.

I do a lot of work connected to various networks via IPSec VPN using the FortiClient. I have no problem with Nmap in a terminal window, but Zenmap will not work across the VPN.

I just tried a vpn-connected /24 and Nmap found the expected 12 hosts up in 5 seconds. Using the same scan, Zenmap found zero.

The Mac Mini has a single ethernet adapter enabled (WLAN turned off). Just for grins I also connected the VPN before launching Zenmap. I also changed to WLAN only and got the same results.

Both Zenmap and Nmap work on the three local VLANs, though Zenmap is more accurate. It makes no sense to me that Zenmap and Nmap in Terminal would get different results.

[dmiller-nmap]

What is the output in the terminal of nmap --version? What about if you put nmap --version in Zenmap's "Command:" window and press "Scan"? It's possible you have multiple versions installed.

The other very likely possibility is that you are running nmap in the terminal without using sudo, so it's using TCP Connect scan, but Zenmap is running with its authorization wrapper (it prompted you for your sudo password when you ran it) and can use SYN scan. TCP Connect scan can work with more interface types and VPNs because it relies on the OS's socket API, but SYN scan is faster when it does work. Try adding --unprivileged to your command in Zenmap and see if it fixes it.

Let us know what you find out; it's possible we could improve support for this VPN.