Description

SRX345 DNS query through fxp0 does not work when fxp0 belongs to routing instance mgmt_junos .

Symptoms

SRX345 DNS query through fxp0 doesn't work when fxp0 belongs to routing instance mgmt_junos

Configure DNS and fxp0 as below:

set system management-instance
set system name-server 10.85.128.1 routing-instance mgmt_junos
set interfaces fxp0 unit 0 family inet address 10.85.242.142/25
set routing-options static route 0.0.0.0/0 next-hop 10.85.242.129
set routing-instances mgmt_junos routing-options static route 0.0.0.0/0 next-hop 10.85.242.129

SRX can ping DNS server IP address, but DNS does not work:

{primary:node0}[edit]
root@router# run show route table mgmt_junos.inet.0

mgmt_junos.inet.0: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

0.0.0.0/0          *[Static/5] 15:07:25
                    >  to 10.85.242.129 via fxp0.0
10.85.242.128/25   *[Direct/0] 15:07:26
                    >  via fxp0.0
10.85.242.142/32   *[Local/0] 15:07:26
                       Local via fxp0.0

{primary:node0}
root@router> ping routing-instance mgmt_junos 10.85.128.1 rapid count 5
PING 10.85.128.1 (10.85.128.1): 56 data bytes
!!!!!
--- 10.85.128.1 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.128/3.034/14.286/5.627 ms

{primary:node0}
root@router> ping routing-instance mgmt_junos www.juniper.net
ping: cannot resolve www.juniper.net: Host name lookup failure

Solution

Regarding Management Interface in a Non-default Instance and DNS configuration, refer to the following technical documentation:.

DNS query through fxp0 is not supported on SRX Branch platform when fxp0 belongs to routing instance mgmt_junos. This is a limitation.