Junos OS

Hi.

I understand that creating the mgmt_junos instance creates a seperate routing table for the fxp0 interface, but what is the benefit of doing this?

I ask this because by default, transit traffic can't pass from a regular network interface (eg xe-0/0/0) to the management interface fxp0 anyway. 

So what is the benefit of placing the fxp0 management interface in the mgmt_junos instance?

Many thanks,

Deepak

Hi.

If you want to have a default route for mgmt and also have a default route for transit data, what do you do if you don't have mgmt_junos?

Hi,

it creates a routing table of it's own and the table stays only in RE. you can hook up system services from RE to mgmt_junos only, you can source traffic to authentication server (radius + tacacs) and many other protocols like NTP and it keeps all the management services isolated. protects it from attacks in the default routing table. it basically secures or saperates the routing engine communication with the management systems.

in future it will support newer features.

i am here if i missed anything to answer or if more clarification required.

Without the mgmt_junos instance, the management interface shares the default inet.0 routing table with the main routing instance. By enabling mgmt_junos, management routes are kept in a dedicated routing instance, providing clear separation from production routes. Using management VRF also makes it easier to direct specific management processes such as DNS, NTP, or AAA, which improves both troubleshooting and traffic separation.

Example:
set system ntp server x.x.x.x routing-instance mgmt_junos