--- title: Inter-VRF DHCP Relaying with Redundant DHCP Servers «... description: A deep-dive lab test exploring inter-VRF DHCP relaying with redundant DHCP servers. The post traces the full DHCP handshake — DISCOVER, OFFER, REQUEST, ACK,... canonical: https://daily.dev/posts/inter-vrf-dhcp-relaying-with-redundant-dhcp-servers-ipspace-net-blog-5yadyd3sy twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Inter-VRF DHCP Relaying with Redundant DHCP Servers « ipSpace.net blog | daily.dev og:description: A deep-dive lab test exploring inter-VRF DHCP relaying with redundant DHCP servers. The post traces the full DHCP handshake — DISCOVER, OFFER, REQUEST, ACK,... og:url: https://daily.dev/posts/inter-vrf-dhcp-relaying-with-redundant-dhcp-servers-ipspace-net-blog-5yadyd3sy og:image: https://api.daily.dev/og/posts/5YADYd3Sy.png og:image:alt: Inter-VRF DHCP Relaying with Redundant DHCP Servers « ipSpace.net blog og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Inter-VRF DHCP Relaying with Redundant DHCP Servers « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 11 min read · 0 upvotes · 0 comments ## Summary A deep-dive lab test exploring inter-VRF DHCP relaying with redundant DHCP servers. The post traces the full DHCP handshake — DISCOVER, OFFER, REQUEST, ACK, and lease renewal — showing how the server-id-override option allows DHCP servers to masquerade as the relay's VLAN IP, enabling the protocol to function across VRFs despite multiple protocol violations. The non-selected server receives confused REQUEST messages but avoids sending DHCPNAK due to server-id-override awareness. The conclusion: the setup works with Cisco IOS clients and IOS XE servers, but strict RFC implementations may misbehave, so lab testing before production deployment is essential. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How does inter-VRF DHCP relaying work with redundant DHCP servers and what problems does it cause? Inter-VRF DHCP relaying with redundant servers works but causes protocol violations at several steps. The relay uses server-id-override to present its own VLAN IP as the DHCP server address, so clients bind to the relay rather than the real server. The non-selected server receives DHCP REQUEST messages for unexpected addresses and logs confusion, but suppresses DHCPNAK responses specifically because server-id-override is detected. Cisco IOS clients and IOS XE servers handle this correctly; strict RFC implementations may not. _Network engineers deploying this pattern in production track implementation-specific gotchas like these on daily.dev._ ### What does 'Not sending DHCPNAK due to Server-id-override' mean on a Cisco IOS XE DHCP server? It means the DHCP server detected that the incoming REQUEST references an IP address it did not assign, but it is suppressing the DHCPNAK because the server-id-override option is present. In inter-VRF relaying, the relay advertises its own VLAN IP as the server identifier, so the non-selected server sees a REQUEST for an address it never offered. Rather than disrupting the client with a NAK, it silently drops the transaction. _Engineers troubleshooting DHCP in VRF environments find edge-case explanations like this faster by following networking topics on daily.dev._ --- [View this post on daily.dev](https://daily.dev/posts/inter-vrf-dhcp-relaying-with-redundant-dhcp-servers-ipspace-net-blog-5yadyd3sy) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Inter-VRF DHCP Relaying with Redundant DHCP Servers « ipSpace.net blog","url":"https://daily.dev/posts/inter-vrf-dhcp-relaying-with-redundant-dhcp-servers-ipspace-net-blog-5yadyd3sy","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/inter-vrf-dhcp-relaying-with-redundant-dhcp-servers-ipspace-net-blog-5yadyd3sy"},"datePublished":"2026-08-11T08:56:09.521Z","dateModified":"2026-08-11T09:06:31.255Z","description":"A deep-dive lab test exploring inter-VRF DHCP relaying with redundant DHCP servers. 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The relay uses server-id-override to present its own VLAN IP as the DHCP server address, so clients bind to the relay rather than the real server. The non-selected server receives DHCP REQUEST messages for unexpected addresses and logs confusion, but suppresses DHCPNAK responses specifically because server-id-override is detected. Cisco IOS clients and IOS XE servers handle this correctly; strict RFC implementations may not. Network engineers deploying this pattern in production track implementation-specific gotchas like these on daily.dev."}},{"@type":"Question","name":"What does 'Not sending DHCPNAK due to Server-id-override' mean on a Cisco IOS XE DHCP server?","acceptedAnswer":{"@type":"Answer","text":"It means the DHCP server detected that the incoming REQUEST references an IP address it did not assign, but it is suppressing the DHCPNAK because the server-id-override option is present. In inter-VRF relaying, the relay advertises its own VLAN IP as the server identifier, so the non-selected server sees a REQUEST for an address it never offered. Rather than disrupting the client with a NAK, it silently drops the transaction. Engineers troubleshooting DHCP in VRF environments find edge-case explanations like this faster by following networking topics on daily.dev."}}]} ```