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Cisco to Juniper Command Cheat Sheet: A Practical Junos Guide

Moving from Cisco to Juniper? Compare IOS and Junos commands for interfaces, VLANs, OSPF, BGP and safe commits, with practical engineering examples.

By Tosin Otuniyi, Founder and Network and Security Architect ·

Cisco to Juniper: the engineer’s practical cheat sheet by Compritech

A Cisco to Juniper command cheat sheet helps network engineers translate familiar IOS and IOS XE tasks into Junos commands. The biggest change is the configuration workflow: Junos uses a candidate configuration, reviewed and activated through a commit.

This guide covers interface checks, access ports, trunks, static routes, OSPF, BGP troubleshooting and rollback. For UK businesses planning an infrastructure refresh, it also explains the checks that should accompany a Cisco-to-Juniper migration.

Compritech provides Cisco and Juniper network engineering services, including onsite support, commissioning, migrations and decommissioning.

Scope: Cisco examples use familiar IOS/IOS XE syntax. They are not universal NX-OS or IOS XR commands. Junos examples use common routing syntax and ELS-style EX/QFX switching. Older non-ELS switches, MX bridging, SRX security and Junos OS Evolved can differ. Use ? and the documentation for your exact platform and release. Configuration examples are separate lab snippets, not one combined deployment script.

1. Learn this before learning any command translation

In a typical IOS/IOS XE CLI session, configuration commands alter the running configuration as you enter them. Saving makes that configuration survive a restart.

Junos gives you a candidate configuration. You edit it, review the difference, and commit it to activate and save the change.

That makes this sequence worth learning early:

configure exclusive
top
show | compare
commit check
commit confirmed 5

Insert your intended configuration changes before show | compare. configure exclusive locks the shared candidate while you work; coordinate with other engineers and inspect any pre-existing changes.

commit check validates the candidate; it does not prove that traffic will flow. commit confirmed 5 activates it with a five-minute automatic rollback timer.

Verify management access, affected services and traffic from the appropriate vantage points. Then, while still in configuration mode:

commit
exit

If you do not confirm in time, Junos returns to the previous committed configuration. It is a useful protection for remote changes, alongside a tested recovery path.

A detail engineers can miss: on documented Junos behaviour, commit check can also confirm a pending confirmed commit. Run validation before the timed commit, and only confirm after checking the result.

2. The everyday command translation sheet

These are commands for similar tasks, not a promise that the outputs or semantics are identical.

TaskCisco IOS / IOS XEJunos operational mode
Software and modelshow versionshow version
Active configurationshow running-configshow configuration
Interface overviewshow ip interface briefshow interfaces terse
Interface descriptionsshow interfaces descriptionshow interfaces descriptions
Detailed port countersshow interfaces GigabitEthernet1/0/1show interfaces ge-0/0/1 extensive
IPv4 routing tableshow ip routeshow route table inet.0
ARP entriesshow ip arpshow arp
LLDP neighboursshow lldp neighborsshow lldp neighbors
MAC learningshow mac address-tableshow ethernet-switching table
VLANsshow vlan briefshow vlans
Switchport / trunk stateshow interfaces switchport / show interfaces trunkshow ethernet-switching interfaces
OSPF neighboursshow ip ospf neighborshow ospf neighbor
BGP sessionsshow ip bgp summaryshow bgp summary
System logsshow loggingshow log messages
Hardware inventoryshow inventoryshow chassis hardware

On routed platforms, switching commands may not apply. Use LLDP for multi-vendor neighbour discovery; CDP and LLDP are different protocols.

3. Understand the prompt—and stop getting stuck in the wrong mode

In the Junos CLI, > normally indicates operational mode and # configuration mode. The hierarchy marker, such as [edit interfaces], tells you where configuration commands will apply.

configure
edit interfaces ge-0/0/1
show
up
top

edit moves into a hierarchy, up moves back one level, and top returns to the root. Run the full-path set examples below from [edit].

Need operational output without leaving configuration mode?

run show interfaces terse
run show bgp summary

Want the active configuration as reusable set statements? In operational mode:

show configuration | display set

In configuration mode, show | display set shows the candidate at your current hierarchy. That distinction matters when checking whether a change is already live.

4. Four shortcuts that make troubleshooting faster

show interfaces terse | match "ge-0/0/"
show log messages | last 30
show configuration interfaces | display set
show route table inet.0 | no-more

Use match to filter, last to see recent lines and no-more to disable pagination for that command. Add ? to discover available options instead of guessing the syntax.

For an intermittent link problem, start with:

show interfaces ge-0/0/1 extensive
show interfaces diagnostics optics ge-0/0/1
show log messages | match "ge-0/0/1"

Optics diagnostics depend on hardware and transceiver support. Look at errors, carrier transitions and supported optical readings before changing configuration.

5. Configure a routed interface

Cisco IOS/IOS XE example, on a routed port:

interface GigabitEthernet1/0/1
 description LAB-P2P
 ip address 192.0.2.1 255.255.255.252
 no shutdown

A switchport may require conversion to a routed port first, where supported.

Junos candidate configuration, from [edit]:

set interfaces ge-0/0/1 description LAB-P2P
set interfaces ge-0/0/1 unit 0 family inet address 192.0.2.1/30

If disable is configured at the physical interface, remove that statement to enable it:

delete interfaces ge-0/0/1 disable

Check for logical-unit disable statements and incompatible existing switching configuration too. unit 0 is the logical interface; family inet means IPv4. Review and commit before expecting these changes in operational output.

6. Access ports and trunks: the ELS translation

Create VLAN 10 and an access port on an ELS-style Junos switch:

set vlans USERS vlan-id 10
set interfaces ge-0/0/2 unit 0 family ethernet-switching interface-mode access
set interfaces ge-0/0/2 unit 0 family ethernet-switching vlan members USERS

The familiar Cisco shape is:

vlan 10
 name USERS
interface GigabitEthernet1/0/2
 switchport mode access
 switchport access vlan 10

For a Junos trunk carrying VLANs 10 and 20:

set vlans VOICE vlan-id 20
set interfaces ge-0/0/3 unit 0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/3 unit 0 family ethernet-switching vlan members [ USERS VOICE ]

This assumes USERS already exists. Inspect and remove conflicting previous settings before changing an existing port's role.

Older non-ELS platforms use port-mode in place of interface-mode. Native VLAN handling, spanning-tree interoperability and allowed VLAN lists need explicit checks during a migration.

A trunk being up does not prove that the intended VLANs are forwarding.

7. Static routing and OSPF: familiar concepts, different hierarchy

A Junos lab default route:

set routing-options static route 0.0.0.0/0 next-hop 192.0.2.2

The IOS/IOS XE equivalent:

ip route 0.0.0.0 0.0.0.0 192.0.2.2

Enable OSPF on the logical interface in Junos:

set routing-options router-id 192.0.2.1
set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

After committing, verify:

show ospf neighbor
show ospf interface
show route protocol ospf

Check area, timers, authentication, MTU and network type if adjacency does not form. Changing a router ID on a working device needs separate planning.

8. BGP is established. Where are my prefixes?

Start with these Junos operational commands:

show bgp summary
show bgp neighbor 192.0.2.2
show route receive-protocol bgp 192.0.2.2
show route advertising-protocol bgp 192.0.2.2
show route hidden extensive

They answer different questions: is the peer up, what was received, what was prepared for advertisement, and why might a route be unusable?

Received-route output is not proof that a route is active or installed in forwarding. Hidden-route visibility also depends on what routes the device retains.

For a prefix missing from an advertisement, check the correct routing table, whether the route is active, its next-hop resolution and the export policy. Junos does not automatically export every connected or static route into BGP. Permit only the intended routes with an explicit policy.

An established session proves the session works. It does not prove your routing policy works.

9. Rollback, deactivate and delete: know the difference

From configuration mode at [edit]:

rollback 0

This reloads the current committed configuration into the candidate, discarding pending candidate edits. In shared mode, that can affect other engineers' work.

To load the previous committed configuration:

rollback 1
show | compare

The rollback becomes active only when committed. Review the whole difference: this can revert more than your latest intended change.

To retain a configuration statement but mark it inactive:

deactivate protocols ospf

To restore it:

activate protocols ospf

delete removes a statement from the candidate. These actions still require a commit and can interrupt services; they are separate examples, not a troubleshooting sequence.

10. Five migration mistakes worth avoiding

  1. Treating commit as merely another spelling of write memory. Activation timing differs.
  2. Translating VLAN syntax without checking ELS support and existing port configuration.
  3. Assuming Cisco administrative distance and Junos route preference values are identical. Check route-selection behaviour rather than copying numbers.
  4. Treating an SRX security policy as an interface ACL. Stateful security, zones, host-inbound traffic and NAT require separate design.
  5. Checking neighbour state but skipping application traffic, forwarding, return paths and recovery testing.

The best cheat code is a repeatable method

Capture the baseline. Change one thing deliberately. Review the candidate. Validate. Commit with a recovery plan. Prove the outcome. Document the result.

That method carries across vendors—and makes the command translations useful.

At Compritech, we support Cisco and Juniper network infrastructure through onsite engineering, commissioning, hardware replacement, migrations and decommissioning. Our engineering-led approach connects practical infrastructure work with secure handling of equipment at the end of its service life.

Planning a refresh, migration or onsite engineering project? Explore our network engineering services:

https://compritech.co.uk/network-engineering/

Cisco-to-Juniper migration checklist for UK businesses

A command translation is only one part of a migration. Before replacing equipment, record VLANs, trunks, port channels, routing neighbours, security controls and management dependencies. Confirm supported optics, port speeds, software features and licensing on the replacement platform.

Agree acceptance tests and a rollback decision point before the change window. Test management access, route advertisements, VLAN forwarding, application connectivity, monitoring and return paths. Keep the original equipment available until the agreed checks pass.

Compritech can provide onsite engineering and Smart Hands support for physical installation, patching, hardware replacement and coordinated remote implementation. When equipment is retired, our network decommissioning services support planned removal and end-of-life handling.

Frequently asked questions

What is the Juniper equivalent of show ip interface brief?

Use show interfaces terse in Junos operational mode for a concise interface overview. It includes physical and logical interfaces; the output is not identical to Cisco IOS.

Does Junos apply configuration changes immediately?

Ordinary CLI configuration changes are made to a candidate configuration. They become active when committed. This differs from the typical IOS/IOS XE configuration workflow.

What does commit confirmed 5 do?

It activates the candidate with a five-minute confirmation timer. If the change is not confirmed in time, Junos automatically restores the previous committed configuration. Verify services before confirming it.

Why does my Juniper switch use port-mode instead of interface-mode?

Older non-ELS switching configuration uses port-mode. ELS-style configuration uses interface-mode. Check your switch model, software release and supported configuration style before translating VLAN commands.

Can I convert a Cisco configuration directly into Junos?

Command mappings are a starting point. Interface naming, route selection, routing policies, spanning tree and security behaviour require design review and testing. A text substitution is not a validated migration.

Vendor references for readers

These examples were checked against vendor documentation; they have not been lab-tested on your hardware.