Technologies/Tailscale/tailscale.relay.connection
TailscaleTailscaleMetric

tailscale.relay.connection

Using relay vs direct
Dimensions:None
Available on:Google Cloud MonitoringGoogle Cloud Monitoring (1)

Summary

Binary indicator (0 or 1) showing whether this node is currently using DERP relay servers for connectivity instead of direct peer-to-peer connections. Value of 1 indicates relayed connections, suggesting NAT traversal failure or blocked direct connectivity. Value of 0 confirms direct peer connections are established. Monitor to detect when connections fall back to relays, which degrades performance and increases latency.

Interface Metrics (1)
Google Cloud MonitoringGoogle Cloud Monitoring
Indicates whether the node is using a DERP relay server for connections (1 = relay, 0 = direct)
Dimensions:None
Sources
tailscale.node.relay_connectioncloud.google.com

Technical Annotations (56)

Configuration Parameters (3)
--portrecommended: 0
0 enables auto-selection to avoid port conflicts
PORT
Windows environment variable in tailscaled-env.txt for UDP listen port
/etc/defaults/tailscaledrecommended: port configuration
Linux location to set custom port for tailscaled
Error Signatures (3)
relay "code"log pattern
direct connection not establishedlog pattern
via DERP(log pattern
CLI Commands (14)
tailscale statusdiagnostic
tailscale ping <device>diagnostic
tailscale pingdiagnostic
tailscale netcheckdiagnostic
tailscale versiondiagnostic
mtr serverdiagnostic
rsync -ah --progress /radarr-pool/Tenet\ \(2020\)/Tenet\ \(2020\)\ Bluray-2160p.mkv ~/Downloadsdiagnostic
scp -C ashayc@<redacted>:/radarr-pool/Tenet\ \(2020\)/Tenet\ \(2020\)\ Bluray-2160p.mkv ~/Downloadsdiagnostic
systemctl status tailscaleddiagnostic
tailscale ping 100.64.10.99diagnostic
tailscale debug peer-relay-sessionsdiagnostic
tailscale set --relay-server-port=<port>remediation
tailscale ping <node>diagnostic
tailscale ping <device-name>diagnostic
Technical References (36)
Hard NATconceptDERPcomponenthead-of-line blockingconceptTCP meltdownconceptsubnet routercomponentexit nodecomponentrelay servercomponentNAT traversalconcepttailnetconceptUDPprotocolport mappingconcepttailscaled daemoncomponentdirect connectionconceptDERP relaycomponentMTUconceptWireGuardprotocolport 41641conceptDERP relay serverscomponentMappingVariesByDestIPcomponentpeer relaycomponentC:\ProgramData\Tailscale\tailscaled-env.txtfile pathsymmetric NATconceptCGNATconceptDERP servercomponentNAT-PMPprotocolUPnPprotocolQoSconcepthard NATconceptNAT gatewaycomponentTailscale Peer Relaycomponentapp connectorcomponentNATcomponentdouble NATconceptPCPprotocolSTUNprotocoltailscaledcomponent
Related Insights (34)
Hard NAT causes slow connections and DNS timeouts via DERP relaywarning
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DERP relay usage detected instead of direct connectionsinfo
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High latency or packet loss on internet connections through tailnetwarning
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High latency or packet loss between tailnet peerswarning
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DERP relay fallback degrades performance when direct connection failswarning
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NAT traversal problems prevent direct device connectionswarning
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Outdated Tailscale client versions cause unstable connections and performance degradationwarning
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Exit node routing causes extreme latency increase and bandwidth collapsecritical
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SCP transfers over Tailscale achieve only 0.5-1.5 Mbps despite direct connection and sufficient bandwidthwarning
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Relayed connections reduce network performancewarning
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Tailscale disconnected state despite running daemonwarning
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Traffic relays through DERP instead of direct peer connection causing latencywarning
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UDP connectivity blocked prevents direct WireGuard connections forcing DERP relaywarning
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DERP relay usage indicates direct connectivity failure between peerswarning
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Direct connection failure between home peers despite no restrictive NATwarning
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Peer relay service running but not accepting sessionswarning
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Port conflict on UDP peer-to-peer traffic prevents connectivitycritical
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DERP relay throughput throttling causes severe degradation on intercontinental connectionswarning
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Symmetric NAT prevents direct peer connections forcing DERP relay fallbackwarning
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DERP relay connections indicate direct connection failure or suboptimal routingwarning
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Relayed connection when direct is possible causes performance degradationwarning
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Hard NAT prevents direct connections between deviceswarning
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Blocked UDP packets force fallback to relayed connectionswarning
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Exit node traffic routing through NAT gateway prevents direct connectionswarning
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Peer relay provides better performance than DERP for blocked direct connectionsinfo
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Connection type changes when network conditions deterioratewarning
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NAT traversal failure blocks traditional VPN connectivity in restricted networkswarning
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Hard NAT on both sides forces DERP relay connection degrading performancewarning
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MappingVariesByDestIP indicates hard NAT preventing direct connectionswarning
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UDP field false indicates blocked outbound UDP preventing all direct connectionscritical
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PortMapping false without UPnP/NAT-PMP/PCP support indicates hard NATwarning
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Packet loss on peer connections indicating network instabilitywarning

Packet loss between peers indicates network path instability, congestion, or hardware issues. Even small amounts of packet loss (>1%) can severely impact TCP throughput and latency-sensitive applications, causing retransmissions, increased latency, and degraded user experience.

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DERP relay dependency indicating direct connectivity failurewarning

When peer connections are forced to route through DERP relay servers instead of establishing direct peer-to-peer connections, this indicates NAT traversal failures, firewall restrictions, or network configuration issues. DERP relays add latency and consume additional bandwidth, degrading performance and increasing infrastructure costs.

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Elevated peer latency indicating network path degradationwarning

Sustained increases in peer-to-peer latency indicate network path degradation, increased reliance on DERP relays, or intermediate network congestion. This directly impacts application performance for latency-sensitive workloads and user experience.

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