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Why BGP Gets Stuck in Active State — And How to Fix It

BGP stuck in Active is one of the most common issues in enterprise networks. The Active state means BGP is trying to establish a TCP connection to its neighbor but hasn't succeeded. Here's the systematic approach to diagnose it — with real debug commands and output.

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.0.0.2        4 65002       0       0        0    0    0 00:02:13 Active

The fix starts with confirming TCP reachability, then checking source interface, then MD5 authentication mismatches. The video below walks through all three scenarios with live debug output.

IKEv2 Phase 1 Fails Silently: A Debug Walkthrough

IKEv2 failures are notoriously hard to diagnose because error messages are vague. This walkthrough covers the most common Phase 1 failure causes — encryption mismatch, DH group incompatibility, and pre-shared key errors — with the exact debug commands and what to look for.

IKEv2:(SESSION ID = 1,SA ID = 1):Sending packet to 203.0.113.2
IKEv2:(SESSION ID = 1,SA ID = 1):Failed to find a matching policy
IKEv2:(SESSION ID = 1,SA ID = 1):Abort exchange

Netmiko vs Paramiko: Which One Should You Use?

Both libraries let Python talk to network devices over SSH, but they solve different problems. Paramiko is a raw SSH library — flexible but verbose. Netmiko is built on top of Paramiko specifically for network devices, handling prompt detection, enable mode, and pagination automatically.

from netmiko import ConnectHandler
device = {'device_type': 'cisco_ios', 'host': '10.0.0.1',
          'username': 'admin', 'password': 'cisco'}
conn = ConnectHandler(**device)
output = conn.send_command('show bgp summary')
print(output)