I am using ssh-keyscan to obtain public keys for a couple of SSH servers. One of my appliances only supports DSA / ssh-dss. ssh-keyscan with the "-t dsa" option is not able to get the public key while the Nmap script ssh-hostkey in fact is able to obtain it.
weberjoh@nb15-lx:~$ ssh-keyscan -t dsa ssg-mgmt # ssg-mgmt:22 SSH-2.0-NetScreen
weberjoh@nb15-lx:~$ nmap --script ssh-hostkey ssg-mgmt Starting Nmap 7.01 ( https://nmap.org ) at 2017-10-11 16:00 CEST Nmap scan report for ssg-mgmt (192.168.120.3) Host is up (0.0026s latency). rDNS record for 192.168.120.3: ssg-mgmt.webernetz.net Not shown: 998 filtered ports PORT STATE SERVICE 22/tcp open ssh | ssh-hostkey: |_ 1024 e7:5b:c9:a9:60:60:66:37:d6:90:bd:70:8f:76:e5:41 (DSA) 443/tcp open https Nmap done: 1 IP address (1 host up) scanned in 7.28 seconds
How can I use ssh-keyscan to show the DSA public key?