info.txt

# In .ssh/config:
Host *
    ControlMaster no # Connections by default are not a master
    ControlPath ~/.ssh/master-%r@%h:%p
    ServerAliveInterval 60
    ServerAliveCountMax 60

# On normal connections, if there is no master running on the ControlPath it will behave as normal
ssh some.host

# Run autossh (ftp://ftp.sunfreeware.com/pub/freeware/SOURCES/autossh-1.4b.tar.gz)
autossh -f -M 0 -N -o "ControlMaster yes" some.host

# This will setup a daemon that will maintain a "Master" connection to some.host
# Now ssh will use that master channel to connect to some.host
ssh some.host

testing.txt

[jill@ev3-bastion2-prod ~]$ cat .ssh/config 
Host *
  ControlMaster no
  ControlPath ~/.ssh/master-%r@%h:%p
  ServerAliveInterval 60
  ServerAliveCountMax 60
Host ev3-karma1-a
  User jill
  Hostname 10.100.100.219

[jill@ev3-bastion2-prod ~]$ ps -efo pid,rss,args | grep autossh |grep -v grep
 8647 1132 autossh -f -M 0 -N -o ControlMaster yes ev3-karma1-a
[jill@ev3-bastion2-prod ~]$ netstat -a|grep 10.100.100.219
ev3-bastion2-prod.17062 10.100.100.219.ssh   49640      0 49640      0 ESTABLISHED
ffffff0d57318148 stream-ord ffffff106b4a1600 00000000    /home/jill/.ssh/master-jill@10.100.100.219:22
[jill@ev3-bastion2-prod ~]$ ls -al .ssh/|grep master
srw-------   1 jill     jill           0 Mar 12 15:12 master-jill@10.100.100.219:22