Troubleshooting Junos
Table of Contents
Notes from a Juniper Junos troubleshooting course#
Packets reaching the irb interface trigger a routing lookup.
When using vMX, typically in a lab, then there should be two VMs: one for the control plane and one for the forwarding plane, named something like vmx1-vcp and vmx1-vfp respectively.
When pinging the IP address of an aggregate Ethernet interface, the ICMP Echo Reply packets are duplicated:
lab@vEX> ping 172.16.200.2 count 3
PING 172.16.200.2 (172.16.200.2): 56 data bytes
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.034 ms
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.209 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.251 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.295 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.346 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.387 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.418 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=0 ttl=63 time=3.448 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.641 ms
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.688 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.711 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.717 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.871 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.883 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.919 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=1 ttl=63 time=3.923 ms (DUP!)
64 bytes from 172.16.200.2: icmp_seq=2 ttl=63 time=2.626 ms
--- 172.16.200.2 ping statistics ---
3 packets transmitted, 3 packets received, +14 duplicates, 0% packet loss
round-trip min/avg/max/stddev = 2.626/3.492/3.923/0.343 ms
lab@vEX>
The ‘hot swappable’ and ‘hot pluggable’ are chassis capabilities and are not the same.
A craft interface is the collection of LEDs on a Juniper device.
lab@vEX> show chassis craft-interface
error: FPM slot is empty
lab@vEX>
Checking the FPCs:
lab@vEX> show chassis fpc
Temp CPU Utilization (%) CPU Utilization (%) Memory Utili
zation (%)
Slot State (C) Total Interrupt 1min 5min 15min DRAM (MB) Heap
Buffer
0 Online Testing 7 0 5 6 6 1023 22
0
1 Empty
2 Empty
3 Empty
4 Empty
5 Empty
6 Empty
7 Empty
8 Empty
9 Empty
10 Empty
11 Empty
lab@vEX>
lab@vSRX> show chassis fpc detail
Slot 0 information:
State Online
Total CPU DRAM ---- CPU less FPC ----
Start time 2026-08-27 03:27:56 UTC
Uptime 6 hours, 44 minutes, 42 seconds
lab@vSRX>
Comparing the FPC uptime with the system uptime, it looks like the FPC took about 2,5 minutes to come up after the system came up:
lab@vSRX> show chassis fpc detail
Slot 0 information:
State Online
Total CPU DRAM ---- CPU less FPC ----
Start time 2026-08-27 03:27:56 UTC
Uptime 6 hours, 47 minutes, 33 seconds
lab@vSRX> show system uptime
Current time: 2026-08-27 10:15:33 UTC
Time Source: LOCAL CLOCK
System booted: 2026-08-27 03:26:19 UTC (06:49:14 ago)
Protocols started: 2026-08-27 03:27:16 UTC (06:48:17 ago)
Last configured: 2026-08-27 09:03:45 UTC (01:11:48 ago) by lab
10:15AM up 6:49, 1 users, load averages: 1.73, 2.17, 2.38
lab@vSRX>
Verifying any active alarms on the chassis:
lab@vEX> show chassis alarms
No alarms currently active
lab@vEX>
Setting chassis alarms:
[edit]
lab@vEX# set chassis alarm ?
Possible completions:
+ apply-groups Groups from which to inherit configuration data
+ apply-groups-except Don't inherit configuration data from these groups
> ds1 DS1 alarms
> ethernet Ethernet alarms
> fru-absence FRU module absence
ignore-fan-speed-check Ignore the Fan speed check alarms
> integrated-services Integrated services alarms
> management-ethernet Management Ethernet alarms
> otn-odu OTN ODU alarms
> otn-otu OTN OTU alarms
> serial Serial alarms
> services Services PIC alarms
> sonet SONET alarms
> t3 DS3 alarms
[edit]
lab@vEX#
lab@vMX-1# set chassis alarm ethernet link-down red
[edit]
lab@vMX-1# commit and-quit
kenv: unable to get vmtype
commit complete
Exiting configuration mode
lab@vMX-1> show chassis alarms
4 alarms currently active
Alarm time Class Description
2026-08-27 05:47:48 PDT Major ge-0/0/9: Link down
2026-08-27 05:47:48 PDT Major ge-0/0/8: Link down
2026-08-27 05:47:48 PDT Major ge-0/0/7: Link down
2026-08-27 05:47:48 PDT Major ge-0/0/6: Link down
lab@vMX-1>
Verifying the status of the routing engine with show chassis routing-engine. This is also useful for baselining:
lab@vEX> show chassis routing-engine
Routing Engine status:
Slot 0:
Current state Master
Election priority Master (default)
DRAM 1993 MB (2048 MB installed)
Memory utilization 17 percent
5 sec CPU utilization:
User 0 percent
Background 0 percent
Kernel 3 percent
Interrupt 0 percent
Idle 97 percent
1 min CPU utilization:
User 1 percent
Background 0 percent
Kernel 3 percent
Interrupt 0 percent
Idle 96 percent
5 min CPU utilization:
User 1 percent
Background 0 percent
Kernel 3 percent
Interrupt 0 percent
Idle 96 percent
15 min CPU utilization:
User 1 percent
Background 0 percent
Kernel 3 percent
Interrupt 0 percent
Idle 96 percent
Model RE-VMX
Start time 2026-08-27 03:10:42 UTC
Uptime 6 hours, 1 minute, 26 seconds
Last reboot reason Router rebooted after a normal shutdown.
Load averages: 1 minute 5 minute 15 minute
0.27 0.37 0.66
lab@vEX>
Verifying storage#
lab@vEX> show system storage
Filesystem Size Used Avail Capacity Mounted on
/dev/gpt/junos 20G 882M 17G 5% /.mount
/dev/gpt/config 793M 40K 730M 0% /.mount/config
/dev/gpt/var 7.0G 230M 6.2G 4% /.mount/var
tmpfs 3.0G 8.0K 3.0G 0% /.mount/tmp
tmpfs 332M 740K 332M 0% /.mount/mfs
lab@vEX>
1632 ssh l
lab@vEX> show system directory-usage
/var/home/lab
68K /var/home/lab/jt
8.0K /var/home/lab/.ssh
lab@vEX>
lab@vEX> show system directory-usage /boot
880K /boot
lab@vEX> show system directory-usage /root
/root
3.0K /root/.ssh
lab@vEX>
md51zero
% ls -l /dev/ | less
total 6
crw------- 1 root wheel 0xfb Aug 27 03:12 ack7271
crw------- 1 root wheel 0xfd Aug 27 03:12 ack7323
crw------- 1 root wheel 0xfc Aug 27 03:12 ack7337
crw-rw-r-- 1 root operator 0x26 Aug 27 03:10 acpi
crw-r----- 1 root operator 0x5c Aug 27 03:10 ada0
crw-r----- 1 root operator 0x5f Aug 27 03:10 ada0p1
crw-r----- 1 root operator 0x60 Aug 27 03:10 ada0p2
crw-r----- 1 root operator 0x61 Aug 27 03:10 ada0p3
crw-r----- 1 root operator 0x62 Aug 27 03:10 ada0p4
crw-r----- 1 root operator 0x5d Aug 27 03:10 ada1
crw-r----- 1 root operator 0x63 Aug 27 03:10 ada1p1
crw-r----- 1 root operator 0x64 Aug 27 03:10 ada1p2
crw-r----- 1 root operator 0x65 Aug 27 03:10 ada2
crw-rw-r-- 1 root operator 0x28 Aug 27 03:10 apm
crw-rw---- 1 root operator 0x27 Aug 27 03:10 apmctl
crw------- 1 root kmem 0x20 Aug 27 03:10 audit
crw------- 1 root wheel 0x1f Aug 27 03:10 auditpipe
crw-r----- 1 root kmem 0x2b Aug 27 03:10 bios
crw-r----- 1 root operator 0x5e Aug 27 03:10 cd0
crw------- 1 root wheel 0x7 Aug 27 03:10 console
crw------- 1 root wheel 0x13 Aug 27 03:10 consolectl
crw-rw-rw- 1 root wheel 0x1e Aug 27 03:10 ctty
crw-rw---- 1 uucp dialer 0x2f Aug 27 03:10 cuau0
crw-rw---- 1 uucp dialer 0x30 Aug 27 03:10 cuau0.init
<---- output omitted ---->
Verifying the physical disk, that stores the Junos image, against any errors using the freeBSD dd command. I guess the dd stands for ‘diagnose disk’. In the command arguments:
- an input file with
ifwhich is here the device file that contains the Junos image, - an output file with
ofwhich is here the bit bucket, - the block size with
bs, with a size of 1 Megabyte. This means that both the input file and the output file will be respectively read from and written to using the same block size of 1 Megabyte (1m stands for one Megabyte).
The command takes some minutes to complete.
root@vMX-1:/var/home/lab # dd if=/dev/gpt/junos of=/dev/null bs=1m
20480+0 records in
20480+0 records out
21474836480 bytes transferred in 142.441345 secs (150762663 bytes/sec)
root@vMX-1:/var/home/lab #
root@vMX-1:/var/home/lab #
Snapshotting#
lab@vEX> request system snapshot ?
Possible completions:
<[Enter]> Execute this command
configuration Store device configuration in snapshot
delete Delete an existing snapshot
force Force snapshot operation
load Load a given snapshot and activate it upon reboot
media Media to snapshot to
name Snapshot name
no-configuration Do not store device configuration in snapshot
partition Partition the media
recovery Create a recovery snapshot
| Pipe through a command
lab@vEX> request system snapshot
NOTICE: Snapshot snap.20260827.100557 created successfully
lab@vEX>
lab@vEX> show system snapshot
Non-recovery snapshots:
Snapshot snap.20260827.100557:
Location: /packages/sets/snap.20260827.100557
Configuration: yes
Creation date: Aug 27 10:05:58 2026
Junos version: 25.2R1.8
Total non-recovery snapshots: 1
Recovery Snapshots:
No recovery snapshots available on the OAM volume
lab@vEX>
lab@vEX> start shell
% ls /packages/sets
activesnap.20260827.100557
%
Logs#
Verifying the freeBSD logs:
lab@vEX> file show /var/log/messages | last 10
Aug 27 09:18:51 vEX mgd[9743]: UI_DBASE_LOGOUT_EVENT: User 'lab' exiting configurati
on mode
Aug 27 09:18:52 vEX dcd[7349]: DCD_CONFIG_WRITE_FAILED: IFA em1.0 (family=2) configu
ration write failed for an IFA ADD: Can't assign requested address
Aug 27 09:19:13 vEX last message repeated 2 times
Aug 27 09:21:14 vEX last message repeated 12 times
Aug 27 09:29:51 vEX last message repeated 51 times
Aug 27 09:30:02 vEX dcd[7349]: DCD_CONFIG_WRITE_FAILED: IFA em1.0 (family=2) configu
ration write failed for an IFA ADD: Can't assign requested address
Aug 27 09:30:22 vEX last message repeated 2 times
Aug 27 09:32:13 vEX last message repeated 11 times
lab@vEX>
It seems to me that show log messages displays similar output to file show /var/log/messages:
lab@vEX> show log messages | last 5
Aug 27 09:48:38 vEX sshd[9933]: Accepted publickey for lab from 172.25.11.254 port 4
7788 ssh2: RSA SHA256:bNFHIDQez76VOJpiGUXgKoT9jCJcbomVnX1xFTXDepk
Aug 27 09:48:47 vEX dcd[7349]: DCD_CONFIG_WRITE_FAILED: IFA em1.0 (family=2) configu
ration write failed for an IFA ADD: Can't assign requested address
Aug 27 09:49:17 vEX last message repeated 3 times
lab@vEX>
lab@vEX> file show /var/log/messages | last 5
Aug 27 09:48:38 vEX sshd[9933]: Accepted publickey for lab from 172.25.11.254 port 4
7788 ssh2: RSA SHA256:bNFHIDQez76VOJpiGUXgKoT9jCJcbomVnX1xFTXDepk
Aug 27 09:48:47 vEX dcd[7349]: DCD_CONFIG_WRITE_FAILED: IFA em1.0 (family=2) configu
ration write failed for an IFA ADD: Can't assign requested address
Aug 27 09:49:17 vEX last message repeated 3 times
lab@vEX>
Matching on error messages in the log file:
lab@vEX> show log messages | match error | last 3
Aug 27 03:12:35 vEX na-grpcd[7292]: NA_GRPCD_CONFIG_EDIT_FAILURE: Ephemeral DB Edit
config: error_code=1, error_message='Invalid Request'
Aug 27 09:38:24 vEX mgd[9743]: SWITCHOVER_FETCH_COMMIT_STATUS_FAILED: : Some error o
ccurred while fetching the commit info
lab@vEX>
Displaying log messages matching a date:
lab@vMX-1> show log messages | match "Aug 27"
Aug 27 03:17:32 vMX-1 fpc0 root: /home/pfe/riot/phase2_launch.sh: Waiting for RE to
come up
Aug 27 03:17:32 vMX-1 fpc0 root: /home/pfe/riot/phase2_launch.sh: Starting master pi
ng script
Aug 27 03:17:32 vMX-1 fpc0 root: /home/pfe/riot/phase2_launch.sh: Calling master pin
g script
<---- output omitted ---->
Displaying log messages matching a date and a boot action by piping the search patterns:
lab@vMX-1> show log messages | match "Aug 27" | match boot
Aug 27 03:17:48 vMX-1 fpc0 mpcsd: Cannot open /boot/vmlinuz.ver for reading
Aug 27 03:17:48 vMX-1 fpc0 mpcsd: Cannot open /boot/rootfs.ver for reading
Aug 27 04:48:55 vMX-1 mgd[11863]: UI_REBOOT_EVENT: System rebooted by 'lab'
Aug 27 04:48:55 vMX-1 shutdown[12092]: reboot requested by lab at Thu Aug 27 04:49:5
5 2026
Aug 27 04:49:55 vMX-1 shutdown[12092]: reboot by lab:
Aug 27 04:51:46 vMX-1 eventd[6597]: SYSTEM_SHUTDOWN: System reboot by lab at Thu Aug
27 04:49:55 2026: no message
Aug 27 04:51:47 vMX-1 logger: RC_REBOOT: reason=0x0 reason_string=Normal shutdown
Aug 27 11:52:11 vMX-1 fpc0 mpcsd: Cannot open /boot/vmlinuz.ver for reading
Aug 27 11:52:11 vMX-1 fpc0 mpcsd: Cannot open /boot/rootfs.ver for reading
Aug 27 04:56:29 vMX-1 mgd[7232]: UI_REBOOT_EVENT: System rebooted by 'lab'
Aug 27 04:56:29 vMX-1 shutdown[7604]: reboot requested by lab at Thu Aug 27 05:01:29
2026
lab@vMX-1>
Finding out at what time FPC 0 came online:
lab@vMX-1> ...h "Aug 27" | match fpc | match online | match 0
Aug 27 04:52:22 vMX-1 chassisd[7138]: CHASSISD_SNMP_TRAP7: SNMP trap generated: Fru
Online (jnxFruContentsIndex 7, jnxFruL1Index 1, jnxFruL2Index 0, jnxFruL3Index 0, jnx
FruName FPC: Virtual FPC @ 0/*/*, jnxFruType 3, jnxFruSlot 0)
lab@vMX-1>
Displaying boot messages:
lab@vEX> show system boot-messages | last 6
cd0: quirks=0x40<RETRY_BUSY>
random: randomdev_wait_until_seeded unblock wait
random: Entropy start-up health tests performed on 1024 samples passed.
random: HMAC-DRBG with SHA2-512 chosen
random: unblocking device.
random: HMAC-DRBG: instantiated with 1024 primary SW events, 384 secondary SW Shannon
s, 0 HW Shannons
lab@vEX>
To look for errors that might have occurred at boot time:
lab@vMX-1> show system boot-messages | match error
old_ifname to jnx_re_host_ifd_name, error 2
old_ifname to jnx_re_host_ifd_name, error 2
peer_inputs: 6399: Failed to call the appropriate handler for the peer class: 0, type
: 17, index: 0, vksid: 0, state: 0, if_pfe_msg_handler failed with error: 89
GENCFG: op for 32 (Resync blob) failed; err 7 (Doesn't Exist) minor type: 0x41. Error
originated from pfe type: 17, pfe index: 0, mgmt addr: 0x80000010
GENCFG: op for 32 (Resync blob) failed; err 7 (Doesn't Exist) minor type: 0x41. Error
originated from pfe type: 17, pfe index: 0, mgmt addr: 0x80000010
peer_socket_close: peer 0x80000010 (type 17 index 0), so_error 0, snd sb_state 0x10,
rcv sb_state 0x20
lab@vMX-1>
To read logs on hardware inventory changes:
lab@vSRX> show log invento
error: could not resolve file: invento
lab@vSRX> show log inventory
Aug 3 15:54:00 CHASSISD release 24.4R1.9 built by builder on 2024-12-19 08:02:07 UTC
Aug 3 15:54:00 System IO - part number , serial number
Aug 3 15:54:00 vsrx chassis, serial number
Aug 3 15:54:06 CHASSISD release 24.4R1.9 built by builder on 2024-12-19 08:02:07 UTC
Aug 3 15:54:06 System IO - part number , serial number
<---- output omitted ---->
The routing engine RE#
Trying to switch routing engines on a virtual Junos:
lab@vEX> request chassis routing-engine master ?
Possible completions:
acquire Attempt to become master Routing Engine
release Request that other Routing Engine become master
switch Toggle mastership between Routing Engines
lab@vEX> request chassis routing-engine master switch
error: Could not connect to re1 : No route to host
error: Some error occurred while fetching the commit info
warning: Traffic will be interrupted while the PFE is re-initialized
Toggle mastership between routing engines ? [yes,no] (no) yes
error: Command aborted. The adjacent slot is empty.
lab@vEX>
The packet forwarding engine PFE#
lab@vEX> show pfe statistics error
Slot 0
HSL2 Errors:
------------
***** No errors on this PFE *****
JGCI Errors:
------------
Frames Received (last
) CRC Errors (last)
-----------------------
-----------------------------
lab@vEX>
lab@vSRX> show pfe statistics error
================ tnp_0x1000080 ================
lab@vSRX>
Scheduled reboots#
lab@vEX> request system reboot ?
Possible completions:
<[Enter]> Execute this command
at Time at which to perform the operation in hh::mm 24 hrs format
both-routing-engines Reboot both the Routing Engines
in Number of minutes to delay before operation
junos Boot off Junos volume
message Message to display to all users
network Network boot via PXE
oam Boot off OAM volume
other-routing-engine Reboot the other Routing Engine
power-off Power-off the software on RE
usb Boot off USB device
| Pipe through a command
lab@vEX>
To schedule a reboot:
lab@vMX-1> request system reboot in ?
Possible completions:
<in> Number of minutes to delay before operation
lab@vMX-1> request system reboot in 1
Reboot the system in 1? [yes,no] (no) yes
*** System shutdown message from lab@vMX-1 ***
System going down in 1 minute
Shutdown at Thu Aug 27 04:49:55 2026.
[pid 12092]
Verify if there is a scheduled reboot action:
lab@vMX-1> show system reboot
reboot requested by lab at Thu Aug 27 04:49:55 2026
[process id 12092]
lab@vMX-1>
To abort a scheduled reboot action:
lab@vMX-1> request system reboot in 5
Reboot the system in 5? [yes,no] (no) yes
*** System shutdown message from lab@vMX-1 ***
System going down in 5 minutes
Shutdown at Thu Aug 27 05:01:29 2026.
[pid 7604]
lab@vMX-1> show reboot
^
syntax error, expecting <command>.
lab@vMX-1> show system reboot
reboot requested by lab at Thu Aug 27 05:01:29 2026
[process id 7604]
lab@vMX-1>
lab@vMX-1> clear system reboot
reboot requested by lab at Thu Aug 27 05:01:29 2026
[process id 7604]
Terminating...
lab@vMX-1>
lab@vMX-1> show system reboot
No shutdown/reboot scheduled.
lab@vMX-1>
Chassis hardware:
lab@vEX> show chassis hardware
Hardware inventory:
Item Version Part number Serial number Description
Chassis VM690A4C0B13 EX9214
Midplane
Routing Engine 0 RE-VMX
CB 0 VMX SCB
FPC 0 BUILTIN BUILTIN Virtual FPC
CPU Rev. 1.0 RIOT-LITE BUILTIN
MIC 0 Virtual 20x 1GE(LAN) SFP
PIC 0 BUILTIN BUILTIN Virtual 10x 1GE(LAN) SFP
PIC 1 BUILTIN BUILTIN Virtual 10x 1GE(LAN) SFP
MIC 1 Virtual 4x 10GE(LAN) XFP
PIC 2 BUILTIN BUILTIN Virtual 2x 10GE(LAN) XFP
PIC 3 BUILTIN BUILTIN Virtual 2x 10GE(LAN) XFP
lab@vEX>
show chassis pic-status to get a hint to the number of PFEs on the chassis.
lab@vEX> show chassis fpc pic-status
Slot 0 Online Virtual FPC
PIC 0 Online Virtual 10x 1GE(LAN) SFP
PIC 1 Online Virtual 10x 1GE(LAN) SFP
PIC 2 Online Virtual 2x 10GE(LAN) XFP
PIC 3 Online Virtual 2x 10GE(LAN) XFP
lab@vEX>
1574 ssh
Software and software packages#
lab@vEX> show system software
dsa-x86-64-20250622.231547_builder_junos_252_r1 -- dsa
jail-runtime-x86-32-20250603.72f4182_builder_bsd15_252 -- jail runtime
jdocs-x86-32-20250622.231547_builder_junos_252_r1 -- jdocs
jinsight-x86-32-25.2R1.8 -- jinsight
jmrt-base-x86-64-25.2R1.8 -- jmrt base
jmrt-test-x86-64-25.2R1.8 -- jmrt test
jsd-x86-32-20250622.231547_builder_junos_252_r1-jet-1 -- jsd jet 1
jsim-pfe-vmx-x86-32-20250622.231547_builder_junos_252_r1 -- jsim pfe vmx
jsim-wrlinux-x86-32-20250622.231547_builder_junos_252_r1 -- jsim wrlinux
junos-appidd-mx-x86-32-20250622.231547_builder_junos_252_r1 -- junos appidd mx
junos-bbe-up-x86-64-25.2R1.8 -- junos bbe up
junos-daemons-x86-64-20250622.231547_builder_junos_252_r1 -- junos daemons
junos-daemons-mx-x86-64-20250622.231547_builder_junos_252_r1 -- junos daemons mx
junos-dp-crypto-support-mtx-x86-32-20250622.231547_builder_junos_252_r1 -- junos dp
crypto support mtx
junos-jsqlsync-x86-32-20250622.231547_builder_junos_252_r1 -- junos jsqlsync
junos-km-x86-32-20250622.231547_builder_junos_252_r1 -- junos km
junos-l2-rsi-20250622.231547_builder_junos_252_r1 -- junos l2 rsi
junos-libs-x86-64-20250622.231547_builder_junos_252_r1 -- junos libs
junos-libs-compat32-x86-64-20250622.231547_builder_junos_252_r1 -- junos libs compa
t32
junos-libs-compat32-mx-x86-64-20250622.231547_builder_junos_252_r1 -- junos libs co
mpat32 mx
<---- output omitted ---->
Accessing freeBSD#
lab@vMX-1> start shell
%
% whoami
lab
% exit
exit
lab@vMX-1> start shell user lab
lab@vMX-1>
lab@vMX-1> start shell user root
Password:
root@vMX-1:/var/home/lab #
root@vMX-1:/var/home/lab #
#QA Why with the lab user account it was not possible to launch the csh shell?
Configuration files#
Locating the configuration file:
lab@vEX> start shell
%
% pwd
/config
% ls -l
total 64
-rw-r--r-- 1 root wheel 0 Aug 27 03:12 db_ext
-rw-r--r-- 1 root wheel 0 Aug 27 09:03 db_optimize-cfg
-rw-r--r-- 1 root wheel 0 Aug 27 08:40 db_optimize-cfg-
-rw-r--r-- 1 root wheel 0 Aug 27 09:03 dual_phase_bootup.state
-rw-r--r-- 1 root wheel 0 Aug 27 08:40 dual_phase_bootup.state-
-rw-r----- 1 root wheel 1602 Aug 27 08:40 juniper.conf.1.gz
-rw-r----- 1 root wheel 1602 Jan 9 2026 juniper.conf.2.gz
-rw-r----- 1 root wheel 1658 Jan 9 2026 juniper.conf.3.gz
-rw-r----- 1 root wheel 1460 Aug 27 09:03 juniper.conf.gz
-rw-r--r-- 1 root wheel 32 Jan 9 2026 juniper.conf.md5
-rw-r--r-- 1 root wheel 4188 Nov 4 2025 usage.db
drwxr-xr-x 2 root wheel 512 Nov 4 2025 vchassis
%
Junos processes#
Finding out whether a specific process is running by piping it to show system processes:
lab@vMX-1> show system processes | match rpd
7254 - S 0:00.09 /usr/sbin/rpdtmd -N
7272 - S 0:01.24 /usr/sbin/rpd -N
lab@vMX-1>
Restarting processes with the restart command, for example the rpd process:
lab@vSRX> show route
inet.0: 11 destinations, 12 routes (11 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
0.0.0.0/0 *[Static/5] 10:16:55
> to 172.18.1.1 via ge-0/0/0.0
[Static/7] 10:16:55
> to 172.18.2.1 via ge-0/0/1.0
10.210.0.0/16 *[Static/5] 10:17:23
> to 172.25.11.254 via fxp0.0
172.18.1.0/30 *[Direct/0] 10:16:55
> via ge-0/0/0.0
172.18.1.2/32 *[Local/0] 10:16:55
Local via ge-0/0/0.0
172.18.2.0/30 *[Direct/0] 10:16:55
> via ge-0/0/1.0
172.18.2.2/32 *[Local/0] 10:16:55
Local via ge-0/0/1.0
172.25.11.0/24 *[Direct/0] 10:17:24
> via fxp0.0
172.25.11.3/32 *[Local/0] 10:17:24
Local via fxp0.0
192.168.11.0/24 *[Direct/0] 04:41:08
> via ge-0/0/2.0
192.168.11.2/32 *[Local/0] 04:41:08
Local via ge-0/0/2.0
192.168.31.1/32 *[Direct/0] 10:17:24
> via lo0.0
inet6.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
ff02::2/128 *[INET6/0] 10:16:57
MultiRecv
lab@vSRX>
lab@vSRX> restart routing
Routing protocols process signalled but still running, waiting 28 seconds more
Routing protocols process started, pid 53621
lab@vSRX>
lab@vSRX> show route
inet.0: 11 destinations, 12 routes (11 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
0.0.0.0/0 *[Static/5] 00:00:03
> to 172.18.1.1 via ge-0/0/0.0
[Static/7] 00:00:03
> to 172.18.2.1 via ge-0/0/1.0
10.210.0.0/16 *[Static/5] 00:00:03
> to 172.25.11.254 via fxp0.0
172.18.1.0/30 *[Direct/0] 00:00:03
> via ge-0/0/0.0
172.18.1.2/32 *[Local/0] 00:00:03
Local via ge-0/0/0.0
172.18.2.0/30 *[Direct/0] 00:00:03
> via ge-0/0/1.0
172.18.2.2/32 *[Local/0] 00:00:03
Local via ge-0/0/1.0
172.25.11.0/24 *[Direct/0] 00:00:03
> via fxp0.0
172.25.11.3/32 *[Local/0] 00:00:03
Local via fxp0.0
192.168.11.0/24 *[Direct/0] 00:00:03
> via ge-0/0/2.0
192.168.11.2/32 *[Local/0] 00:00:03
Local via ge-0/0/2.0
192.168.31.1/32 *[Direct/0] 00:00:03
> via lo0.0
inet6.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
ff02::2/128 *[INET6/0] 00:00:03
MultiRecv
lab@vSRX>
Login sessions#
With only one connected user per SSH:
lab@vSRX> show system users
6:37AM up 10:11, 1 user, load averages: 1.84, 2.49, 2.54
USER TTY FROM LOGIN@ IDLE WHAT
lab pts/0 172.25.11.254 6:35AM - -cli (cli)
lab@vSRX>
When a second user logs in:
lab@vSRX> show system users
6:37AM up 10:11, 2 users, load averages: 1.84, 2.44, 2.52
USER TTY FROM LOGIN@ IDLE WHAT
lab pts/0 172.25.11.254 6:35AM - -cli (cli)
lab pts/1 172.25.11.254 6:37AM - -cli (cli)
lab@vSRX>
Kicking out a user session:
lab@vSRX> request system logout ?
Possible completions:
<[Enter]> Execute this command
all Logout all sessions owned by user
pid Management process ID for user
terminal Terminal user is logged in to
user Name of user
| Pipe through a command
lab@vSRX> request system logout user lab ?
Possible completions:
<[Enter]> Execute this command
all Logout all sessions owned by user
pid Management process ID for user
terminal Terminal user is logged in to
| Pipe through a command
lab@vSRX> request system logout user lab terminal ?
Possible completions:
<terminal> Terminal user is logged in to
lab@vSRX> request system logout user lab terminal pts/1
logout-user: done
lab@vSRX> show system users
6:39AM up 10:13, 1 user, load averages: 2.10, 2.33, 2.46
USER TTY FROM LOGIN@ IDLE WHAT
lab pts/0 172.25.11.254 6:35AM - -cli (cli)
lab@vSRX>
Core dumps#
lab@vSRX> show system core-dumps
/var/crash/*core*: No such file or directory
/var/tmp/*core*: No such file or directory
/var/tmp/pics/*core*: No such file or directory
/var/crash/kernel.*: No such file or directory
/var/jails/rest-api/tmp/*core*: No such file or directory
/tftpboot/corefiles/*core*: No such file or directory
lab@vSRX>
The argument for the core dumps is not displayed in the help:
lab@vSRX> request system ?
Possible completions:
certificate Manage X509 certificates
commit Perform commit related operations
configuration Request operation on system configuration
convert-json-configuration Convert the given JSON configuration file as per Junos
debug-info Collect debug information of the system
decrypt Decrypt a $8$ or $9$-encrypted password
download Manage downloads
evpn Show evpn status
firmware Upgrade or downgrade firmware
halt Halt the system
license Manage feature licenses
logout Forcibly end user's CLI login session
malware-scan Scan for malware
personality-file Execute commands related to personality of a device
power-off Power off the software on RE
process Request operation on system process
reboot Reboot the system
recover Recover a specified volume
scripts Manage scripts (commit, op, event)
snapshot Create a normal Junos or a recovery snapshot
software Perform system software extension or upgrade
storage Request operation on system storage
yang Perform YANG schema operations
zeroize Erase all data, including configuration and log files
lab@vSRX>
lab@vSRX> request system core-dump ?
Possible completions:
SDN-Telemetry SDN-Telemetry daemon
adaptive-services Adaptive services process
audit-process Audit process
autoinstallation Autoinstallation daemon
cfm Ethernet OAM connectivity-fault-management process
charged Charging local persistent storage daemon
class-of-service Class-of-service daemon
database-replication Database replication process
dhcp-service Dynamic Host Configuration Protocol process
dialer-services Dial-Out On Demand process
dynamic-flow-capture Dynamic flow capture service
event-processing Event processing process
firewall Firewall daemon
firewall-authentication-service Firewall authentication service process
forwarding Forwarding daemon
helper Port-forwarding daemon
hostname-caching-process Hostname caching process
interface-control Interface daemon
isdn-signaling ISDN signaling process
jflow Traffic sampling daemon
jsrp-service Juniper stateful redundancy service process
l2-control Layer 2 control protocols
l2-learning Layer 2 address flooding/learning process
l2tp-service Layer 2 Tunneling Protocol daemon
l2tp-universal-edge Universal edge Layer 2 Tunneling Protocol daemon
lacp Link Aggregation Control Protocol
lfm Ethernet OAM link-fault-management process
management Management daemon
<---- output omitted ---->
Generating core-dump files for the rpd daemon. In my lab, it took more than 10 minutes and still the dumps are not generated:
lab@vSRX> request system core-dump routing
Generating core dump for routing process using running method
Available Free space 11520974Kb, Estimated Required free space 340398Kb
lab@vSRX>
lab@vSRX> show system core-dumps
/var/crash/*core*: No such file or directory
/var/tmp/*core*: No such file or directory
/var/tmp/pics/*core*: No such file or directory
/var/crash/kernel.*: No such file or directory
/var/jails/rest-api/tmp/*core*: No such file or directory
/tftpboot/corefiles/*core*: No such file or directory
lab@vSRX>
Junos commands that are less relevant in a virtual setup#
lab@vEX> show chassis environment
lab@vEX>
To park a message on the Craft interface, where a technician who’s doing show chassis craft-interface will find it, do set chassis display message. The command is not supported on vJunos-switch:
lab@vEX> set chassis display message "guys please swap RE1 at maint. window"
error: command is not valid on the ex9214
lab@vEX>
lab@vEX> show chassis temperature-thresholds
lab@vEX>