The first version of the ScanSSH protocol scanner was released in September 2000. You can download the current version below.
To build ScanSSH, you need to install libevent and libdnet.
The ScanSSH protocol scanner is distributed under a 4-clause BSD-license and completely free for any use including commercial.
$ scanssh -p -e excludes 10.0.0.0/24
[...] 10.0.0.17:23 <refused> 10.0.0.5:6588 <refused> 10.0.0.5:1080 SOCKS v5 10.0.0.5:8080 http proxy 10.0.0.2:23 <timeout> 10.0.0.141:23 <timeout> 10.0.0.17:23 <timeout> 10.0.0.23:22 SSH-1.99-OpenSSH_3.8 10.0.0.195:80 Apache/2.0.30 (Unix) mod_ssl/2.2 10.0.0.5:22 SSH-1.99-OpenSSH_3.6.1 [...]