TechnitiumSoftware/DnsServer · error · ArgumentOutOfRangeException

Valid range is from 1 to 10.

Error message

Valid range is from 1 to 10.

What it means

Thrown by the ResolverRetries property setter when the value is outside [1, 10]. This controls how many times the internal resolver retries an upstream query before giving up. Values below 1 would disable retries entirely (not permitted) and above 10 would waste time on dead upstreams.

Source

Thrown at DnsServerCore/Dns/DnsServer.cs:7921

        public bool QnameMinimization
        {
            get { return _qnameMinimization; }
            set { _qnameMinimization = value; }
        }

        public bool LocallyServedDnsZones
        {
            get { return _locallyServedDnsZones; }
            set { _locallyServedDnsZones = value; }
        }

        public int ResolverRetries
        {
            get { return _resolverRetries; }
            set
            {
                if ((value < 1) || (value > 10))
                    throw new ArgumentOutOfRangeException(nameof(ResolverRetries), "Valid range is from 1 to 10.");

                _resolverRetries = value;
            }
        }

        public int ResolverTimeout
        {
            get { return _resolverTimeout; }
            set
            {
                if ((value < 1000) || (value > 10000))
                    throw new ArgumentOutOfRangeException(nameof(ResolverTimeout), "Valid range is from 1000 to 10000.");

                _resolverTimeout = value;
            }
        }

        public int ResolverConcurrency

View on GitHub (pinned to d0484b6c1e)

Solutions

1. Pick a value between 1 and 10 inclusive (2–3 is a sensible default for most setups).
2. If you wanted to minimize latency, use a lower value like 1–2 rather than 0.
3. Validate config-sourced integers with a range clamp before assignment.

Example fix

// before
server.ResolverRetries = 0;

// after
server.ResolverRetries = 2;

static int ClampRetries(int v) => Math.Clamp(v, 1, 10);
server.ResolverRetries = ClampRetries(configRetries);

static bool IsValidResolverRetries(int v) => v >= 1 && v <= 10;

try { server.ResolverRetries = retries; }
catch (ArgumentOutOfRangeException) { server.ResolverRetries = 2; }

When it happens

Trigger: Setting DnsServer.ResolverRetries to 0, a negative number, or any integer greater than 10.

Common situations: Configuring retries from a UI/env var without bounds checking; setting 0 expecting "no retries"; raising it high hoping for more resilience against flaky upstreams.

Related errors

• Valid range is from 1 to 4.
• Valid range is from 10 to 30.
• Serve stale max wait time valid range is 0 to 1800 milliseco
• TSIG keys cannot have more than 255 entries.
• Value cannot be less than 1.

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/cd3e7fee99e1eca5. Report an issue: GitHub.