Friday, January 20, 2012

Junos router initial login and configuration

Ok, I've built a small mixed Cisco/Juniper Network for OSPF studying and here is some of what I've learned as I go.

To start with, after dragging your Junos device(assuming you have your QEMU junos instance, or however you are getting to Junos up in GNS3), you will open console and get this, or something similar:

Note: when getting out of Junos windows, you have to ctrl+Alt. 

It's important to note that this boot process on your machine may take quite awhile. I don't know if it is processor or ram limited, but on my fairly robust Core i5 box with 16 gb ram, it takes 5 minutes or so. Some people on the GNS3 forums were making the assumption that they weren't getting in, I think, simply because they didn't wait long enough.

Eventually you will get a login prompt.

(you won't see the password request  on first access)

At the login prompt, you will want to enter ROOT access, so amazingly, you type "ROOT" Which will get you to the root access. Then to get to CLI from there, if a password has not been set, you once again, surprisingly, type "CLI" ;-)
And then you are here...

now to enter config level, you can type configure, or Edit.

From here, for example, you can configure the host-name etc.

FYI, if you want to run show commands from configure level, like using "do" in IOS, you need to type "run"

I'll run a show interface for the ethernet 0 interface. Note: The interface is named "em0"

To save any changes in the Junos, you will have to set the Root-Authentication. This allows multiple options but for training sake, I'm using a Plain-Text-password.

Once this is set, you can use the "commit" command to save the configuration.

That's all for now. I'll add a configuring an interface post later tonight.


Yeah, obviously haven't gotten to this yet. Probably tonight.


  1. Hi! What should I do to connect a Juniper router to a Cisco router? When I'm trying to do this I'm receiving this error: "203-Bad number of parameters (5 with min/max=6/6)". There is no problem connecting two Juniper routers, or two Cisco routers, just cannot connect between Cisco and Juniper. Thank you!

  2. I just solved the problem; it's working fine now, with GNS3-0.7.4 - the error above was in GNS3-0.8.2-BETA2. :)

  3. So there are issues with Junos and 0.8.2-BETA2? Good to know! Thanks for posting that!

  4. Nope. There are issues with 0.8.2-BETA2. I try to connect qemu-microcore with cisco3750 and same error "203-Bad number of parameters (5 with min/max=6/6)". Have no idea what is causing that :/

  5. Maybe you have to use the virtual box now. Not sure how you would set that up for the Olive instance.

  6. And the solution is to download once more time the 0.8.2-BETA2 (newer version).
    Now it works just fine.

  7. Cool, thanks for posting!

    Any other reason to upgrade?

  8. Good to know that, maybe I'll give it another try. Ayway, with 0.7.4 working just fine, now I'm in the right track to JNCIP. Good luck to you all, Shawn, I'll keep an eye on your blog. :)