Managing Junos Commit Time

17 09 2015

I’ve been working with an ISP that is going to be using a large amount of configuration in the ‘groups’ section.  The statements there will be inherited into the main configuration using the ‘apply-groups’ statement.

This is a clever way of writing commands once and having them apply to multiple parts of the configuration.  At a basic level you could match on interfaces beginning with ‘ge-‘ or ‘xe-‘ and set an MTU on them all using one group statement. This MTU setting would not appear in the main configuration unless the configuration was displayed using “show | display inheritance”. There’s a nice explanation of how groups work over at this Packetpushers blog.

The downside is that if large amounts of configuration work is done in groups, applying the config can become slow during the ‘commit’ process.   Read the rest of this entry »





Networking Heresy?

14 09 2015

Software Defined Networking, and it’s latest incarnation SD-WAN seem to be all the rage at the moment.  Having seen presentations from vendors large and small on the subject recently at Networking Field Day 10 I am still given to thinking there are a few things that get glossed-over by the vendors quite often.  Foremost in my mind, is this (potentially heretical thought): Read the rest of this entry »





Another useful SRX command for looking at IPSec tunnels

12 08 2015

This is a new one on me – obviously I’ve not been paying much attention since it has been around since 10.2!

On 12.1X45-D15.5 the counters for packets/bytes all show zero, but at least you can see that your tunnel is up and what the various parameters in use are…  See below: Read the rest of this entry »





Useful SRX debugging blog

12 08 2015

Just came across a useful debugging guide for site-to-site IPSec VPNs on Juniper SRX. It is a bit confusing because in steps 2 and 3, where it says [LOCAL PEER IP] it should actually say [REMOTE PEER IP].   But otherwise, this is a very useful set of instructions. Read the rest of this entry »





A nice SRX command I’ve never come across before

11 08 2015

Not sure why this command has to be so obscure, but I stumbled on this while writing a training course tonight – quite a nice way to see if packets are hitting your policies:

imtech@srx220-1-POD3> show security policies hit-count 
Logical system: root-logical-system
 Index   From zone        To zone           Name           Policy count
 1       VR3a             VR3b              P1             0            
 2       VR3a             untrust           3to1VPN        8320         
 3       VR3a             untrust           P1             3249         
 4       VR3b             VR3a              P1             0            
 5       VR3b             untrust           P1             0            
 6       untrust          junos-host        P1             8            
 7       untrust          VR3a              1to3           5523         
 8       untrust          VR3a              P1             5            
 9       untrust          VR3b              permit-to-3b   0            
 10      untrust          VR3b              DEFAULT-DENY   16




Junosphere – inaccessible VMXes

24 07 2015

Update:  The problem described in this article was logged with JTAC.  It took a while but eventually they informed me they had resolved an issue with provisioning VMX in the Junosphere system.  I have tried it since and the issue does appear to have gone away.  However I am leaving this post up in case it has simply become more intermittent.   Please let me know if you experience a situation like what is described below.

I usually use the ‘experimental’ VMX in my Junosphere topologies because I don’t like the VJX all that much.  The VJX has security code in it, so it’s not quite like an MX really.   Also I’ve seen oddities where it came up in flow mode with a default firewall policy of denying everything, and I was never able to work out why.

So instead I use the VMX for everything – which is better these days because it doesn’t use two VM units for the data and control planes like it used to.  Why VMX is still ‘experimental’ after so long is a mystery to me.

However one thing just keeps cropping up with this that is just a bit annoying.   Read the rest of this entry »





Junos Space backup location

30 06 2015

Just a note for future reference: Read the rest of this entry »





VIRL versus Junosphere

9 06 2015

I’ve been using Junosphere a lot recently, and it’s a great tool – quick and easy creation of topologies without the need to go to a physical lab to try things out. Takes the guesswork out of a lot of things, which is a real bonus. There are obviously a few things you can’t do in a virtual environment that would be possible in a real one (e.g. QoS, MTU greater than 2000 bytes, MS-MIC in an MX), but it caters for 80% of what you need.

I always thought that it put Juniper leagues ahead of Cisco because you can buy credits to use the system right on the front page. Cisco were late to the party with something called VIRL – Virtual Internet Routing Lab.  They were late, but rumour had it that a lot of developers moved from Juniper to Cisco to bring VIRL about.  However Junosphere always had the edge for the networking student (as we all remain, whether we are JNCIE or not) because of its accessibility – with VIRL you had to be a Cisco customer and gain access through your account manager.  I’ll stick with GNS3 thanks!

That appears to have changed now, and you can get access to VIRL ‘personal edition’ for $199 per year.  Now we’re talking.  Since it runs on Openstack, you can run up other third-party VMs alongside NXOS, IOS and IOS-XE.  Network Inferno has a nice guide on integrating Juniper’s vSRX (formerly Firefly) into VIRL, which looks pretty comprehensive, although I’ve not tried it yet.

I think need to get a copy of this – only problem is it needs me to get a new quad-core laptop with the virtualization extensions in the BIOS to replace my cranky old Lenovo.  Ho hum!





First steps with Python and Junos

27 04 2015

I’m just spending the day trying to get my head around some very basic automation, so I thought I would install Python 2.7 and work through some of the tutorials on the Techwiki to see how I get on.

Read the rest of this entry »





Remote port-mirroring in Junos

20 03 2015

Information on remote port mirroring on Junos routers doesn’t seem to be very easy to come by for some reason – there is quite a lot of information about doing this on EX switches (a bit like RSPAN in Cisco’s IOS), which wasn’t what I needed.  Various other sources of information (such as Cluepon) say this can be done using a GRE tunnel, but that the capturing device needs to be a server that terminates the GRE tunnel – which all seemed a bit complicated.

I needed to remotely mirror a port on an MX to a second MX where a windows-based Wireshark was connected, so getting GRE working to a Windows host sounded like a non starter.

So I had to work it out myself – and hopefully this write-up will prove useful to someone else in the future. Read the rest of this entry »