{"record":{"id":"3797d0be0d606ca0","repo":"netbirdio/netbird","slug":"create-chain-s-w","errorCode":null,"errorMessage":"create chain %s: %w","messagePattern":"create chain (.+?): %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"client/firewall/iptables/router_linux.go","lineNumber":1054,"sourceCode":"\t}\n\n\tr.updateState()\n\treturn nil\n}\n\n// ensureNATOutputChain lazily creates the OUTPUT NAT chain and jump rule on first use.\nfunc (r *router) ensureNATOutputChain() error {\n\tif _, exists := r.rules[jumpNatOutput]; exists {\n\t\treturn nil\n\t}\n\n\tchainExists, err := r.iptablesClient.ChainExists(tableNat, chainNATOutput)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"check chain %s: %w\", chainNATOutput, err)\n\t}\n\tif !chainExists {\n\t\tif err := r.iptablesClient.NewChain(tableNat, chainNATOutput); err != nil {\n\t\t\treturn fmt.Errorf(\"create chain %s: %w\", chainNATOutput, err)\n\t\t}\n\t}\n\n\tjumpRule := []string{\"-j\", chainNATOutput}\n\tif err := r.iptablesClient.Insert(tableNat, \"OUTPUT\", 1, jumpRule...); err != nil {\n\t\tif !chainExists {\n\t\t\tif delErr := r.iptablesClient.ClearAndDeleteChain(tableNat, chainNATOutput); delErr != nil {\n\t\t\t\tlog.Warnf(\"failed to rollback chain %s: %v\", chainNATOutput, delErr)\n\t\t\t}\n\t\t}\n\t\treturn fmt.Errorf(\"add OUTPUT jump rule: %w\", err)\n\t}\n\tr.rules[jumpNatOutput] = jumpRule\n\n\tr.updateState()\n\treturn nil\n}\n","sourceCodeStart":1036,"sourceCodeEnd":1072,"githubUrl":"https://github.com/netbirdio/netbird/blob/93e97f4bf1ad715072dcb3fb6cdb1763431b5a9c/client/firewall/iptables/router_linux.go#L1036-L1072","documentation":"Error \"create chain %s: %w\" thrown in netbirdio/netbird.","triggerScenarios":"Thrown at client/firewall/iptables/router_linux.go:1054 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"93e97f4bf1ad715072dcb3fb6cdb1763431b5a9c","analyzedAt":"2026-08-16T03:09:19.136Z","schemaVersion":2},"datasetVersion":"2026-08-16T08:17:34.114Z"}