show ip protocols
Displays the current state of all IP routing protocols running on the router, including timers, filters, and network advertisements.
Definition: show ip protocols is a Cisco IOS privileged exec command. Displays the current state of all IP routing protocols running on the router, including timers, filters, and network advertisements.
Overview
The 'show ip protocols' command is a fundamental diagnostic tool for any network engineer working with dynamic routing protocols on Cisco IOS devices. It provides a consolidated view of all IP routing protocols currently configured and running on the router, including their operational parameters, timers, route filters, and redistribution settings. This command is essential for verifying protocol configurations, troubleshooting routing issues, and understanding how the router is participating in the routing domain.
Unlike more protocol-specific commands like 'show ip ospf neighbor' or 'show ip eigrp topology', 'show ip protocols' gives a high-level summary across all protocols, making it the first command to reach for when you need a quick health check of the routing process. It reveals critical information such as which networks are being advertised, whether route filtering is applied, the administrative distance values, and the current routing protocol timers. This command fits into the broader troubleshooting workflow as an initial assessment step: after verifying basic connectivity with 'ping' and 'traceroute', you would use 'show ip protocols' to confirm that routing protocols are running and exchanging routes correctly.
It is also invaluable during configuration audits to ensure that routing updates are only being sent and received on the intended interfaces. In terms of IOS behavior, the output is typically buffered and can be lengthy if multiple protocols are configured; it is available in privileged EXEC mode (enable) and does not require any special privilege level beyond 15. Importantly, this command does not affect the running configuration—it is purely a show command.
Understanding the output of 'show ip protocols' is crucial for CCNA and CCNP candidates as it ties together concepts of routing protocol operation, administrative distance, route filtering, and redistribution, all of which are core to the certification exams.
show ip protocolsWhen to Use This Command
- Verify that routing protocols are configured correctly after initial setup
- Troubleshoot why routes are not being learned or advertised by checking passive interfaces and redistribution
- Check routing protocol timers (e.g., hello/dead intervals) when neighbor relationships are flapping
- Audit route filtering and administrative distances to understand routing behavior
Command Examples
Basic show ip protocols output for EIGRP and OSPF
show ip protocols*** IP Routing is NSF aware ***
Routing Protocol is "application"
Sending updates every 0 seconds
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: application
Routing Protocol is "eigrp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP-IPv4 Protocol for AS(100)
Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
NSF-aware route hold timer is 240
Router-ID: 192.168.1.1
Topology : 0 (base)
Active Timer: 3 min
Distance: internal 90 external 170
Maximum path: 4
Maximum hopcount 100
Maximum metric variance 1
Automatic Summarization: disabled
Maximum path: 4
Routing for Networks:
10.0.0.0
Passive Interface(s):
GigabitEthernet0/1
Routing Information Sources:
Gateway Distance Last Update
10.0.0.2 90 00:12:34
Distance: internal 90 external 170
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 192.168.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 0
Routing Information Sources:
Gateway Distance Last Update
192.168.1.2 110 00:10:05
Distance: (default is 110)
Reference bandwidth unit is 100 mbpsThe output shows two routing protocols: EIGRP AS 100 and OSPF 1. For EIGRP, key fields include K-values (metric weights), Router-ID, active timer, distances (internal 90, external 170), maximum paths, networks being advertised (10.0.0.0), passive interfaces (Gig0/1), and routing information sources (neighbor 10.0.0.2 with last update time). For OSPF, key fields are Router-ID, number of areas (1 normal), networks (192.168.1.0/24 area 0), routing information sources (192.168.1.2), and default distance (110). The reference bandwidth unit is also shown.
Show ip protocols with route filtering and redistribution
show ip protocols*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 10.0.0.1
Number of areas in this router is 2. 1 normal 1 stub
Maximum path: 4
Routing for Networks:
10.0.0.0 0.0.0.255 area 0
192.168.1.0 0.0.0.255 area 1
Passive Interface(s):
Loopback0
Routing Information Sources:
Gateway Distance Last Update
10.0.0.2 110 00:05:20
192.168.1.2 110 00:03:45
Distance: (default is 110)
Reference bandwidth unit is 100 mbps
Routing Protocol is "rip"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Sending updates every 30 seconds, next due in 12 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Redistributing: rip, ospf 1
Default version control: send version 2, receive version 2
Interface Send Recv Triggered RIP Key-chain
GigabitEthernet0/0 2 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
172.16.0.0
Passive Interface(s):
GigabitEthernet0/1
Routing Information Sources:
Gateway Distance Last Update
(none)
Distance: (default is 120)This output shows OSPF with two areas (area 0 normal, area 1 stub) and RIP with redistribution from OSPF. For RIP, timers are shown (30s update, 180s invalid/holddown, 240s flush). Redistribution is indicated under 'Redistributing: rip, ospf 1'. Version control shows send/receive version 2 on Gig0/0. Passive interfaces are listed. RIP has no routing information sources yet. Note the distance: OSPF default 110, RIP default 120.
Understanding the Output
The 'show ip protocols' command provides a comprehensive summary of all IP routing protocols configured on the router. The output is organized per protocol. Key sections include: protocol name and AS/process ID; filter lists (outgoing/incoming); timers (update, invalid, holddown, flush for distance-vector protocols like RIP; hello/dead for link-state are not shown here but in protocol-specific commands); redistribution statements; default version control (RIP); automatic summarization status; maximum paths; networks being advertised (under 'Routing for Networks'); passive interfaces; routing information sources (neighbors with distance and last update time); and administrative distances (internal/external for EIGRP, default for others).
For OSPF, also shows number of areas and their types. For EIGRP, shows K-values, Router-ID, active timer, and metric variance. Good values: timers should match neighbors, distances should be appropriate (e.g., EIGRP internal 90, OSPF 110, RIP 120), routing information sources should list expected neighbors with recent last update times.
Bad values: missing neighbors, stale last update times, incorrect distances, or unexpected passive interfaces. Watch for redistribution loops or missing networks.
Configuration Scenarios
Verify OSPF Configuration on a Single Router
A network engineer has configured OSPF on a router and wants to verify that the correct networks are being advertised, the router ID is set, and the timers are correct before connecting to neighbors.
Topology
R1 (Loopback0: 1.1.1.1/32, Gi0/0: 10.0.12.1/24) --- 10.0.12.0/24 --- R2Steps
- 1.Step 1: Enter privileged EXEC mode: Router> enable
- 2.Step 2: Run the show ip protocols command: Router# show ip protocols
- 3.Step 3: Examine the output for OSPF section: verify Router ID, networks advertised, timers (hello/dead), and any passive interfaces.
- 4.Step 4: If OSPF is not listed, verify OSPF configuration in global config mode.
! OSPF configuration on R1 Router(config)# router ospf 1 Router(config-router)# router-id 1.1.1.1 Router(config-router)# network 10.0.12.0 0.0.0.255 area 0 Router(config-router)# network 1.1.1.1 0.0.0.0 area 0 Router(config-router)# passive-interface default Router(config-router)# no passive-interface GigabitEthernet0/0
Verify: Command: show ip protocols | section OSPF Expected output includes: 'Routing Protocol is "ospf 1"', 'Router ID 1.1.1.1', 'Number of areas: 1', 'Routing for Networks: 10.0.12.0/24, 1.1.1.1/32', 'Passive Interface(s): Loopback0'
Watch out: A common mistake is forgetting to set the router ID manually; if not set, the router will use the highest loopback IP or highest interface IP, which may change if interfaces go down. Always set router-id explicitly.
Verify Route Redistribution Between EIGRP and OSPF
A network engineer has configured mutual redistribution between EIGRP and OSPF on a border router. They need to verify that redistribution is active and that route filters are applied correctly.
Topology
R1 (EIGRP AS 100) --- 10.0.12.0/24 --- R2 (Border) --- 10.0.23.0/24 --- R3 (OSPF area 0)Steps
- 1.Step 1: Enter privileged EXEC mode: Router> enable
- 2.Step 2: Run show ip protocols: Router# show ip protocols
- 3.Step 3: Look for the redistribution section under each protocol. For EIGRP, check if 'Redistributing: ospf 1' is listed with any route-map.
- 4.Step 4: Verify that the route-map referenced exists and is correctly configured.
- 5.Step 5: Check administrative distances to ensure they are appropriate for redistributed routes.
! Redistribution configuration on R2 Router(config)# router eigrp 100 Router(config-router)# redistribute ospf 1 metric 10000 100 255 1 1500 Router(config-router)# exit Router(config)# router ospf 1 Router(config-router)# redistribute eigrp 100 subnets route-map EIGRP-to-OSPF Router(config-router)# exit Router(config)# route-map EIGRP-to-OSPF permit 10 Router(config-route-map)# match ip address prefix-list EIGRP_ROUTES Router(config-route-map)# exit Router(config)# ip prefix-list EIGRP_ROUTES permit 192.168.0.0/16
Verify: Command: show ip protocols | include Redistributing Expected output: Under EIGRP: 'Redistributing: ospf 1'; Under OSPF: 'Redistributing: eigrp 100' with route-map EIGRP-to-OSPF. Also verify with 'show ip route' to see redistributed routes.
Watch out: A common mistake is forgetting the 'subnets' keyword when redistributing into OSPF; without it, only classful networks are redistributed, causing missing routes.
Troubleshooting with This Command
When troubleshooting routing issues, 'show ip protocols' is your first stop to confirm that routing protocols are actually running and configured correctly. A healthy output will list each configured protocol with its process ID, router ID, routing for networks, passive interfaces, redistribution settings, and timers. Key indicators of problems include: missing protocols (protocol not listed at all), incorrect router ID (e.g., 0.0.0.0 or unexpected IP), 'Routing for Networks' missing expected networks, or 'Maximum path' set to an unexpected value.
If a protocol is not listed, check that it is configured under 'router <protocol>' and that the router has at least one network statement or is redistributing routes. For OSPF, verify that the router ID is not 0.0.0.0 (which indicates the router ID is not set). For EIGRP, check that the autonomous system number matches neighbors.
Pay special attention to the 'Routing Information Sources' field: it lists neighbor routers that are sending updates. If no neighbors are listed, the router is not receiving routing updates, which could be due to misconfigured network statements, passive interfaces, or ACLs blocking routing protocol traffic. The 'Distance' section shows administrative distances; if you see unexpected values (e.g., 200 for OSPF), redistribution or distance commands may be misconfigured.
The 'Filtering' section lists distribute-lists, prefix-lists, or route-maps applied to inbound or outbound updates. If routes are missing, check if a filter is inadvertently blocking them. A step-by-step diagnostic flow: 1) Run 'show ip protocols' to get an overview. 2) If a protocol is missing, check configuration. 3) If networks are missing, verify network statements. 4) If neighbors are missing, check interface states and passive interface settings. 5) If routes are missing but neighbors exist, check redistribution and filters. 6) Correlate with 'show ip route' to see which routes are actually installed.
For deeper protocol-specific issues, use 'show ip ospf neighbor', 'show ip eigrp neighbors', or 'debug ip routing'. The output of 'show ip protocols' can also reveal timer mismatches: for example, if OSPF hello timer is 30 seconds instead of the default 10, it may indicate a manual change or a mismatch with neighbors. Always compare timers with neighboring routers using 'show ip ospf interface' or 'show ip eigrp interface'.
CCNA Exam Tips
CCNA exam tip 1: Know the default administrative distances: EIGRP internal 90, OSPF 110, RIP 120, and that EIGRP external is 170.
CCNA exam tip 2: The 'Routing for Networks' section shows which networks are being advertised; if a network is missing, routes won't be propagated.
CCNA exam tip 3: Passive interfaces are shown; remember that a passive interface does not send routing updates but still receives them (for OSPF, it does not form adjacencies).
CCNA exam tip 4: The 'Routing Information Sources' table lists neighbors; if a neighbor is missing or last update is old, suspect a neighbor issue.
Common Mistakes
Mistake 1: Confusing 'Passive Interface(s)' with 'shutdown' — passive interfaces still participate in routing but do not send updates; they are not disabled.
Mistake 2: Assuming 'show ip protocols' shows all routes — it only shows protocol configuration, not the actual routing table (use 'show ip route').
Mistake 3: Overlooking redistribution statements — if redistribution is misconfigured, routes may be missing or suboptimal.
show ip protocols vs show ip route
Both 'show ip protocols' and 'show ip route' are essential for troubleshooting routing issues, but they serve different purposes. The former reveals how routing protocols are configured and their operational state, while the latter displays the resulting IP routing table. They are often confused because both relate to routing, but one focuses on the process and the other on the outcome.
| Aspect | show ip protocols | show ip route |
|---|---|---|
| Scope | Routing protocol configuration and state | IP routing table entries |
| Information Provided | Protocol timers, networks, filters, neighbors | Route prefixes, AD, metric, next-hop, interface |
| Typical Use | Verify protocol settings and adjacencies | Check active routes and forwarding decisions |
| Persistence | Reflects configured protocols and their parameters | Changes dynamically with routing updates and topology changes |
| Precedence | Shows routing processes running on the router | Shows the best routes selected by routing table decision process |
Use show ip protocols when you need to verify routing protocol configuration, timers, or network advertisements, or troubleshoot neighbor relationships.
Use show ip route when you need to view the actual forwarding table, including which routes are installed and their metrics, to troubleshoot reachability or path selection.
Platform Notes
In IOS-XE (e.g., Catalyst 9000 switches), the 'show ip protocols' command syntax and output are nearly identical to classic IOS, but some fields may differ slightly, such as the display of VRF information. On NX-OS (e.g., Nexus switches), the equivalent command is 'show ip protocols' as well, but the output is structured differently and may require specifying the VRF (e.g., 'show ip protocols vrf default'). NX-OS also supports 'show ip ospf', 'show ip eigrp', etc., but the unified 'show ip protocols' provides a summary.
On ASA firewalls, there is no direct equivalent; routing protocol information is viewed via 'show route', 'show ospf', or 'show eigrp' commands. In IOS-XR, the command is 'show ip protocols' but the output is more detailed and includes protocol-specific sections; additionally, IOS-XR uses a different configuration model (XML-based) and the command may require 'detail' keyword for full output. Between IOS versions, the output format has remained largely consistent from 12.x to 15.x and 16.x, but newer versions may include additional fields like 'Graceful Restart' or 'NSF' information.
Always check the specific platform documentation for exact syntax variations.
Related Commands
show ip eigrp neighbors
Displays all EIGRP neighbours with their addresses, interfaces, hold time, uptime, SRTT (smooth round-trip time), RTO, queue count, and sequence numbers.
show ip ospf neighbor
Displays OSPF neighbour table showing router IDs, adjacency state, dead timer, and the interface the neighbour is reachable through.
show ip route
Displays the IP routing table showing all known routes, their source protocols, administrative distances, metrics, next-hops, and outgoing interfaces.
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