Tag Archives: prompt

So much time wasted for such a stupid problem

Let me preface this by saying that remotely rebooting a router/firewall always has associated risks; however, this one may never cross your mind as I’ve found out the hard way.  Apparently, Juniper does not want you to have a Cisco terminal server (aka reverse telnet) connected to their devices’ console ports.

I had been planning on upgrading from JUNOS 11.4R1.6 to the latest 12.1 release because I’ve noticed some weird/undocumented issues with its DHCP server implementation (to make a long story short, DHCP acknowledgments were taking excessively long to process and send out in response to a request).  After the old “request system software add … reboot” command I sat and patiently waited for the box to come back to life; unfortunately, it never did.

Almost by accident, I stumbled upon Juniper KB17145 entitled “SRX reboot can have problems when console cable is connected to Cisco terminal server.”  My favorite sentence is: “misconfiguration on the Cisco port can cause SRX not to boot properly”

This is how Juniper wants you to configure the Cisco serial port:

line aux 0
  session-timeout 7200
  exec-timeout 0 0
  no exec
  transport preferred none
  transport input all
  stopbits 1

So I applied their recommended configuration, rebooted the SRX, and magically, it booted properly!