BGP.guru

BGP.guru

A Nerd blog.

24 Jun 2025

Mikrotik CRS3xx Switching

MikroTik CRS3xx series switch evaluation: comparing CRS309-1G-8S+IN and CRS328-24P-4S+ models, tracking feature progression through RouterOS versions (spanning-tree, port isolation, DHCP snooping, MLAG support, VXLAN), and multi-vendor interoperability with HPE/Cisco switches.
23 Jun 2025

Duplicate MAC Address Madness

Troubleshooting duplicate MAC addresses in redundant firewall HA deployments: discovering non-unique VRRP group IDs across sites caused site-to-site traffic loss, with MAC addresses appearing on unexpected switch ports during failover events.
22 Jun 2025

RouterOS 7.x Filtering

Implementing comprehensive BGP filtering policies on RouterOS 7.x: defining community lists for roles (customer/transit/peering), configuring route protection and RPKI validation, applying per-link inbound/outbound filters with prefix size validation and community-based localpref manipulation.
29 Apr 2024

Syncing RouterOS address-lists

Pull-based RouterOS address-list synchronization using dynamic webserver scripts: generating conditional add/update commands from database backend, fetching and executing scripts on multiple routers, tracking updates with timestamps, and avoiding API version compatibility issues.
23 Apr 2024

RPKI w/ RouterOS v7

Implementing RPKI route validation on RouterOS v7 with routinator RTR server: configuring RTR connections with preference/failover, validating routes with routing filter rules, rejecting invalid routes while preferencing valid routes, and managing ROA growth tracking.