Courseiva
RoutingPrivileged EXEC

show ip protocols

Displays the current state of all IP routing protocols running on the router, including timers, filters, and network advertisements.

Syntax·Privileged EXEC
show ip protocols

When 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 mbps

The 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.

CCNA Exam Tips

1.

CCNA exam tip 1: Know the default administrative distances: EIGRP internal 90, OSPF 110, RIP 120, and that EIGRP external is 170.

2.

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.

3.

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).

4.

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.

Related Commands

show ip eigrp neighbors

Displays the neighbor table for EIGRP, showing all directly connected EIGRP routers and their status, used to verify EIGRP adjacencies and troubleshoot neighbor relationships.

show ip ospf neighbor

Displays OSPF neighbor information to verify adjacency formation and troubleshoot OSPF neighbor relationships.

show ip route

Displays the current IP routing table on a Cisco router, used to verify routes, check next-hop addresses, and troubleshoot connectivity issues.

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