--- title: Nexus OS Fails to Send Syslog Records to a Silent Host «... description: Cisco Nexus OS fails to send syslog messages to a directly connected host until something else populates its ARP cache. Testing with Nexus OS 10.6(2) connected... canonical: https://daily.dev/posts/nexus-os-fails-to-send-syslog-records-to-a-silent-host-ipspace-net-blog-ik6zq4n0x twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Nexus OS Fails to Send Syslog Records to a Silent Host « ipSpace.net blog | daily.dev og:description: Cisco Nexus OS fails to send syslog messages to a directly connected host until something else populates its ARP cache. Testing with Nexus OS 10.6(2) connected... og:url: https://daily.dev/posts/nexus-os-fails-to-send-syslog-records-to-a-silent-host-ipspace-net-blog-ik6zq4n0x og:image: https://api.daily.dev/og/posts/IK6zq4n0x.png og:image:alt: Nexus OS Fails to Send Syslog Records to a Silent Host « 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. # Nexus OS Fails to Send Syslog Records to a Silent Host « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 6 min read · 0 upvotes · 0 comments ## Summary Cisco Nexus OS fails to send syslog messages to a directly connected host until something else populates its ARP cache. Testing with Nexus OS 10.6(2) connected to a dnsmasq container running rsyslogd, the author configured a syslog server but tcpdump showed no UDP traffic and the ARP cache stayed empty. Pinging the syslog server populated the ARP entry, but logging messages still weren't sent immediately. A later config change finally triggered an ARP request and the buffered syslog messages went out, one of them nine minutes after it was generated. Nexus OS buffers syslog messages but never triggers the ARP request needed to deliver them. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### why isn't my Cisco Nexus switch sending syslog messages to my log server even though logging is configured Nexus OS can buffer syslog messages without ever triggering the ARP request needed to resolve the destination, so the packets never leave the switch. In one case on Nexus OS 10.6(2), a syslog message sat buffered for nine minutes before it was finally sent, only after a ping or another config event caused an ARP request. Check 'show ip arp' for an empty entry as a sign this is happening. _Troubleshooting silent Nexus OS logging gaps is the kind of networking edge case developers track on daily.dev._ ## Similar posts on daily.dev - [Using Syslog in netlab Labs « ipSpace.net blog](https://daily.dev/posts/using-syslog-in-netlab-labs-ipspace-net-blog-7rxkh458s) · ipSpace.net Blog · 0 upvotes · 0 comments - [Amazon CloudWatch Logs supports managed syslog ingestion](https://daily.dev/posts/amazon-cloudwatch-logs-supports-managed-syslog-ingestion-plcjxirtu) · AWS · 0 upvotes · 0 comments - [netlab 26.09: Syslog, More DNS, Netmiko « ipSpace.net blog](https://daily.dev/posts/netlab-26-09-syslog-more-dns-netmiko-ipspace-net-blog-7hzbp4smq) · ipSpace.net Blog · 0 upvotes · 0 comments - [I turned on IPv6 to future-proof my network, and it quietly wrecked my latency](https://daily.dev/posts/i-turned-on-ipv6-to-future-proof-my-network-and-it-quietly-wrecked-my-latency-f75enl4hp) · XDA Developers · 1 upvotes · 0 comments --- Tags: [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/nexus-os-fails-to-send-syslog-records-to-a-silent-host-ipspace-net-blog-ik6zq4n0x) ```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":"Nexus OS Fails to Send Syslog Records to a Silent Host « ipSpace.net blog","url":"https://daily.dev/posts/nexus-os-fails-to-send-syslog-records-to-a-silent-host-ipspace-net-blog-ik6zq4n0x","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/nexus-os-fails-to-send-syslog-records-to-a-silent-host-ipspace-net-blog-ik6zq4n0x"},"datePublished":"2026-10-27T10:30:15.211Z","dateModified":"2026-10-27T10:30:46.685Z","description":"Cisco Nexus OS fails to send syslog messages to a directly connected host until something else populates its ARP cache. 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