TechnitiumSoftware/DnsServer · error · InvalidOperationException

Local end point group map contains an invalid end point

Error message

Local end point group map contains an invalid end point: {localEP}

What it means

Thrown while parsing the AdvancedBlockingApp 'localEndPointGroupMap' JSON object in the app config. Each map key is passed to EndPointExtensions.TryParse (expects an IP:port endpoint like '192.168.1.5:53'); when parsing fails the key is rejected as invalid. The error is an InvalidOperationException raised during app initialization, so the app fails to load the config.

Solutions

1. Open dnsApp.config and fix the offending 'localEndPointGroupMap' key so it is a valid IP endpoint with a port (e.g. change '192.168.1.10' to '192.168.1.10:53').
2. Verify the key matches the client's local source endpoint as the server observes it; for IPv6 use bracketed form like '[fe80::1]:53'.
3. If you intended a subnet-based group, move that entry into 'networkGroupMap' instead, which accepts CIDR notation.

Example fix

// before (dnsApp.config)
"localEndPointGroupMap": { "192.168.1.10": "groupA" }
// after
"localEndPointGroupMap": { "192.168.1.10:53": "groupA" }

// Validate every 'localEndPointGroupMap' key is a parseable endpoint before applying config.
foreach (string key in localEndPointGroupMapKeys)
{
    if (!EndPointExtensions.TryParse(key, out EndPoint _))
        throw new FormatException($"'localEndPointGroupMap' key '{key}' is not a valid IP:port endpoint. Expected e.g. '192.168.1.10:53'.");
}

static bool IsValidLocalEndPointKey(string key) => EndPointExtensions.TryParse(key, out EndPoint _);

When it happens

Trigger: Calling the AdvancedBlockingApp initializer with a 'localEndPointGroupMap' whose key string is not a parseable endpoint (e.g. a bare IP without a port, a hostname, '0.0.0.0', or a malformed address like '999.1.1.1:53'). EndPointExtensions.TryParse returns false for that key.

Common situations: Copying a subnet value from 'networkGroupMap' into 'localEndPointGroupMap' (CIDR notation like '10.0.0.0/24' is rejected because endpoints require a port); forgetting the ':53' port; pasting a hostname instead of an IP.

Related errors

• Network group map contains an invalid network address
• Unexpected URL format
• Failed to update web server config. Please try again.
• Forwarder was not defined
• Groups array was not defined.

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/9a2d99d02d01e65f. Report an issue: GitHub.

Appendix: source

Thrown at Apps/AdvancedBlockingApp/App.cs:370

                throw new InvalidOperationException();

            Directory.CreateDirectory(Path.Combine(_dnsServer.ApplicationFolder, "blocklists"));
            using JsonDocument jsonDocument = JsonDocument.Parse(config, _jsonParseOptions);
            JsonElement jsonConfig = jsonDocument.RootElement;

            _enableBlocking = jsonConfig.GetPropertyValue("enableBlocking", true);
            _blockingAnswerTtl = jsonConfig.GetPropertyValue("blockingAnswerTtl", 30u);
            _blockListUrlUpdateIntervalHours = jsonConfig.GetPropertyValue("blockListUrlUpdateIntervalHours", 24);
            _blockListUrlUpdateIntervalMinutes = jsonConfig.GetPropertyValue("blockListUrlUpdateIntervalMinutes", 0);

            _soaRecord = new DnsSOARecordData(_dnsServer.ServerDomain, _dnsServer.ResponsiblePerson.Address, 1, 14400, 3600, 604800, _blockingAnswerTtl);
            _nsRecord = new DnsNSRecordData(_dnsServer.ServerDomain);

            if (jsonConfig.TryReadObjectAsMap("localEndPointGroupMap",
                delegate (string localEP, JsonElement jsonGroup)
                {
                    if (!EndPointExtensions.TryParse(localEP, out EndPoint ep))
                        throw new InvalidOperationException("Local end point group map contains an invalid end point: " + localEP);

                    return new Tuple<EndPoint, string>(ep, jsonGroup.GetString() ?? "");
                },
                out Dictionary<EndPoint, string>? localEndPointGroupMap))
            {
                _localEndPointGroupMap = localEndPointGroupMap;
            }

            _networkGroupMap = jsonConfig.ReadObjectAsMap("networkGroupMap", delegate (string network, JsonElement jsonGroup)
            {
                if (!NetworkAddress.TryParse(network, out NetworkAddress networkAddress))
                    throw new InvalidOperationException("Network group map contains an invalid network address: " + network);

                return new Tuple<NetworkAddress, string>(networkAddress, jsonGroup.GetString() ?? "");
            });

            {
                Dictionary<Uri, BlockList> allAllowListZones = new Dictionary<Uri, BlockList>(0);

View on GitHub (pinned to d0484b6c1e)