junos

Excluding interfaces from IRB State Calculations

As you know, in order you have an IRB up, you need to have at least one interface up on the VLAN for which the IRB is created. This condition is sometimes forgot by engineers troubleshooting why an IRB or RVI or SVI(in Cisco terms) is down. By default all interfaces part of the VLAN… Keep reading »

Proxy ARP on Junos

In this post I will discuss about Proxy ARP feature on Junos, more exactly on EX4200 platform. When a host sends an ARP Request to a switch configured with Proxy ARP, the switch send its own MAC address to resolve the ARP for the destination host and the source host starts to used the switch… Keep reading »

Short Reach Mode on QFX5100-48T

In this post I will discuss about short reach mode feature that is present on QFX5100-48T platform. QFX5100-48T-6Q platform has 48 10BASE-T ports and 6 QSFP+ ports. The short reach mode feature allows to save up to 5W of power usage in case it is activated on the 10BASE-T ports that use cables that are… Keep reading »

Recovery installation on EX9200

The recovery installation is used to restore the factory default installation in case the device software gets corrupted. Once the software gets restored, the device will have the default configuration and it will be needed to either recreate manually the configuration that was running on the device prior the software corruption or to use a… Keep reading »

Link aggregation between Juniper and Linux

I had recently to configure link aggregation between a Linux host and a Juniper device. On Linux this is called bonding and the logical interface is usually called bondX. On Juniper this is called link aggregation and the logical interface is called aggregated ethernet, aeX. For this example I used Ubuntu and based on the… Keep reading »

Consistent Management IP address

I was asked recently by a less experienced colleague of mine if there is a way to configure a single IP address that you can always use to connect to the master Routing Engine of a device that supports dual Routing Engine. My colleague already knew about re0 and re1 configuration groups that allows you… Keep reading »

Sending Junos traceoptions to a syslog server

We discussed in this post how to enable remote tracing on Junos. The problem is that the feature can be enabled only for some specific processes. There is another way how to send any traceoptions to a syslog server. It’s not a Junos specific feature, but a combination of different Junos and Linux/Unix features. Let’s… Keep reading »

Conditional default route advertising

A default route is helping you to send packets to a device when you don’t have specific routing information about the destination of the packets hoping that the device will know how to route the packets to the destination. But it’s not always true. The device advertising the default route might not know how to… Keep reading »

Sidebar