title: SSH on Linux: Disabling host key checking for hosts on local subnet (known_hosts)
body: <p>I work on a network where the systems at an IP address will change frequently.  They are moved on and off the workbench and DHCP determines the IP they get.</p>
  
  <p>It doesn't seem straightforward how to disable host key caching/checking so that I don't have to edit ~/.ssh/known_hosts every time I need to connect to a system.  </p>
  
  <p>I don't care about the host authenticity, they are all on the 10.x.x.x network segment and I'm relatively certain that nobody is MITM'ing me.</p>
  
  <p>Is there a "proper" way to do this? I don't care if it warns me, but halting and causing me to flush my known_hosts entry for that IP every time is annoying and in this scenario it does not really provide any security because I rarely connect to the systems more than once or twice and then the IP is given to another system.  </p>
  
  <p>I looked in the ssh_config file and saw that I can set up groups so that the security of connecting to external machines could be preserved and I could just ignore checking for local addresses.  This would be optimal.</p>
  
  <p>From searching I have found some very strong opinions on the matter, ranging from "Don't mess with it, it is for security, just deal with it" to "This is the stupidest thing I have ever had to deal with, I just want to turn it off" ... I'm somewhere in the middle.  I just want to be able to do my job without having to purge an address from the file every few minutes.</p>
  
  <p>Thanks.</p>