# routing table Published articles for routing table. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## Use of VRF in dual WAN setup DevFeed: [Use of VRF in dual WAN setup]() Original publisher: [Read original article]() Published: 2026-08-03T20:58:23Z Content type: tutorial Language: en Sources: [Personal blog of Anurag Bhatia]() Topics: [networking](), [MikroTik](), [Prometheus](), [Containers]() Tags: [containers](), [mikrotik](), [prometheus](), [router](), [routing](), [routing-table](), [vrf]() ### AI overview This article describes migrating a MikroTik home router from multiple routing tables to a VRF-based dual-WAN design. It explains how shared routing domains caused router-bound traffic to return through the wrong ISP during partial outages and made ISP-specific routing for measurement containers difficult. VRFs provide separate layer-3 routing domains for the WAN links, while Prometheus and Semaphore handle packet-loss-based switchover. ### Source excerpt Over the weekend I migrated my home router from multiple routing tables to a VRF-based design, placing each WAN uplink into its own VRF. While multiple routing tables worked for basic policy routing, they have some limitations and that led to several edge cases that became increasingly difficult to work around. Issues with the setup: If the active default route pointed to ISP1, traffic arriving on ISP1 naturally returned via ISP1. However, traffic terminating on the router and arriving via ISP2 would also be replied to through ISP1, since both uplinks still shared the same routing domain. This did not cause issues for traffic on devices below the router but was bad for traffic terminating on the router interface itself. Due to the above reason, I recently lost access to my home router while I was out of the country because ISP1 had a partial outage (their transit went down, peering stayed up) & due to distributed tooling, the auto switch trigger could not happen either to take care of it. Packets from ISP 2 were being returned via the ISP1 route & thus blackholed. I have a special case where I want most of the devices on a redundant setup but some devices (containers) on specific ISP only. These are measurement containers running blackbox exporter behind a specific ISP as well as RIPE Atlas. I don't want these to switch over for accuracy of measurement. Without VRF it was ugly config-wise, as ISP1 failure will lead to ISP2 routing even when the specific routing table did not have that route. Old Setup My old setup was running multiple routing table pairs: ISP1 only & ISP1 as primary (ISP2 as secondary) ISP2 only & ISP2 as primary (ISP1 as secondary) All WAN interfaces, LAN interfaces and routing tables were in the same single "Main" VRF. This by default takes care of full outage events, fibre cuts, etc. For packet loss-based switchover, I have set up Prometheus + Semaphore as covered in this post last year. Understanding VRF VRF is Virtual Routing and Forwarding. It ## Why Your Traffic Didn't go the way you expected DevFeed: [Why Your Traffic Didn't go the way you expected]() Original publisher: [Read original article]() Author: j2sw Published: 2026-07-28T15:16:02Z Content type: tutorial Language: en Sources: [Justin Wilson (j2sw)]() Topics: [BGP](), [Routing (disambiguation)](), [networking]() Tags: [bgp](), [fd-ix](), [network-engineering](), [network-operations](), [networking](), [peering](), [routing](), [routing-table](), [transit]() ### AI overview This troubleshooting article explains why traffic may not use an expected peering path even when a BGP session is established. It focuses on routing-table selection, Local Preference, BGP policy, and the possibility that return traffic follows a different path. ### Source excerpt 3 Mintue read timeJustin Wilson PacketsDownRange A common problem I run into when diagnosing route issues is traffic not going across the path it's supposed to. An established BGP session only means the routers successfully exchanged routes. It says nothing about which route your router actually installed in the forwarding table. Let's get into some ... Read more The post Why Your Traffic Didn't go the way you expected appeared first on Justin Wilson (j2sw). ## Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes DevFeed: [Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes]() Original publisher: [Read original article]() Author: j2sw Published: 2026-07-24T16:28:00Z Content type: article Language: en Sources: [Justin Wilson (j2sw)]() Topics: [BGP](), [networking](), [Routing (disambiguation)](), [Internet](), [gateway](), [Networks]() Tags: [bgp](), [cpu](), [flexibility](), [internet-architecture](), [isp](), [memory](), [network-engineering](), [network-operations](), [route](), [router](), [routing](), [routing-policy](), [routing-table](), [traffic-engineering](), [visibility]() ### AI overview This article explains BGP route choices, comparing default routes, full routes, partial routes, and customer routes. It describes the tradeoffs between small routing tables, Internet visibility, traffic engineering control, and router resource requirements. ### Source excerpt 5 minute read time.Justin Wilson j2sw.com When you configure a BGP session, one of the first questions is what routes you actually want to receive. If you have ever filled out a questionnaire with Hurricane Electric or another transit provider, they ask you what "kind" of routes you want. In this article, I plan to ... Read more The post Understanding BGP Route Types: Full Routes vs Partial vs Default vs Customer Routes appeared first on Justin Wilson (j2sw). ## The Snapshot Machine: genie learn and diff as a Change-Validation Safety Net on CML2 DevFeed: [The Snapshot Machine: genie learn and diff as a Change-Validation Safety Net on CML2]() Original publisher: [Read original article]() Author: Brent Leekley Published: 2026-06-22T00:00:00Z Content type: tutorial Language: en Sources: [brent.leekley.me blog]() Topics: [networking](), [Cisco](), [Routing (disambiguation)](), [Structured-data](), [Command-line interface]() Tags: [change-validation](), [cisco](), [cisco-modeling-labs](), [cli](), [cml2](), [genie](), [genie-diff](), [genie-learn](), [maintenance-window](), [network-automation](), [network-testing](), [ospf](), [pyats](), [routing-table](), [snapshot](), [structured](), [validation]() ### AI overview This tutorial demonstrates using Cisco Modeling Labs 2 with Genie learn and diff to validate network changes. It snapshots structured operational state before and after a maintenance change, then compares the snapshots to reveal side effects that routine show commands may miss. The source summary reports that a changed OSPF cost reroutes three destinations while adjacencies remain FULL. ### Source excerpt Snapshot a CML2 fabric with genie learn before and after a maintenance change, then genie diff the structured state. One fat-fingered OSPF cost quietly reroutes three destinations while every adjacency stays FULL. Structured before-and-after diffs catch the side effects that show commands miss. ## Picking uncontested private IP subnets with usage data DevFeed: [Picking uncontested private IP subnets with usage data]() Original publisher: [Read original article]() Author: ben@benjojo.co.uk Published: 2025-06-05T10:32:11Z Content type: article Language: en Sources: [benjojo blog]() Topics: [IP routing](), [Networks](), [Virtual Private Network](), [data](), [OpenWrt](), [TLS (Transport Layer Security)]() Tags: [data](), [ip-routing](), [ipv4](), [networks](), [openwrt](), [router](), [routing-table](), [tls](), [vpn](), [wifi]() ### AI overview This article examines how overlapping RFC1918 private IPv4 subnets can prevent routing between networks, including VPN access to an out-of-band network. It uses usage data from consumer network-attached storage devices and their TLS certificates to consider which private subnet ranges may be less likely to collide. ### Source excerpt Picking uncontested private IP subnets with usage data If the device you are reading this on has an IPv4 address, it is very likely not a publicly routeable one. This is because the wide scale dep