Slave_IO_Running = No

We run MySQL replication through stunnel. After rebooting the slaves, sometimes replication won’t start and with SHOW SLAVE STATUS we see Slave_IO_Running = No.
To fix this, I found that I can simply stop and start stunnel and then replication started again!
/etc/init.d/stunnel4 stop
/etc/init.d/stunnel4 start
mysql
show slave status
Slave_IO_Running = Yes
Seconds_Behind_Master = decreasing / catching up…