BGP.guru

BGP.guru

A Nerd blog.

01 Sep 2020

nginx ISP fence

Implementing geographic fencing for nginx applications by ISP networks: using nginx geo module to whitelist IP subnets, aggregating prefixes by source AS from BGP looking glass, and generating dynamic ACL lists for regional access restrictions.
14 Apr 2020

OpenBSD 6.6 BGP Looking Glass

Building BGP looking glass on OpenBSD 6.6 using httpd and bgpd: configuring slowcgi for CGI support, setting up bgplg restricted socket, enabling ping/traceroute in chroot environment, and configuring dual IPv4/IPv6 BGP peering sessions for route lookups.
01 Feb 2020

MPLS Labels Explained

Understanding MPLS label swapping vs stacking: tracing label forwarding tables across router hops showing how labels are replaced at each hop using LDP distribution, with example traceroute output demonstrating label swapping through P/PE routers to destination.
29 Jan 2020

Troubleshooting a Duplicate OSPF Router ID

Troubleshooting OSPF duplicate router IDs in VPLS networks: discovering 10-second route flapping caused by cloned PE router configuration, identifying router ID duplication, and understanding network-wide effects of duplicate router identifiers in MPLS service provider deployments.
19 Jan 2020

Centrally Managed WiFi with MikroTik CAPsMAN

Deploying enterprise WiFi with MikroTik CAPsMAN: configuring centralized management for multiple access points, setting up channels/datapaths/security configs, choosing between local and centralized forwarding, and enabling adaptive noise immunity on Atheros chipsets.