TechnitiumSoftware/DnsServer · error · ArgumentOutOfRangeException

Percentage value valid range is between 0 and 100.

Error message

Percentage value valid range is between 0 and 100.

What it means

Thrown by the QpmLimitUdpTruncationPercentage property setter when the value is below 0 or above 100. This percentage controls how often UDP responses are truncated (TC bit) when QPM limits are exceeded, before the limit hard-blocks queries.

Source

Thrown at DnsServerCore/Dns/DnsServer.cs:7480

        public int QpmLimitSampleMinutes
        {
            get { return _qpmLimitSampleMinutes; }
            set
            {
                if ((value < 1) || (value > 60))
                    throw new ArgumentOutOfRangeException(nameof(QpmLimitSampleMinutes), "Valid range is between 1 and 60 minutes.");

                _qpmLimitSampleMinutes = value;
            }
        }

        public int QpmLimitUdpTruncationPercentage
        {
            get { return _qpmLimitUdpTruncationPercentage; }
            set
            {
                if ((value < 0) || (value > 100))
                    throw new ArgumentOutOfRangeException(nameof(QpmLimitUdpTruncationPercentage), "Percentage value valid range is between 0 and 100.");

                _qpmLimitUdpTruncationPercentage = value;
            }
        }

        public IReadOnlyCollection<NetworkAddress> QpmLimitBypassList
        {
            get { return _qpmLimitBypassList; }
            set
            {
                if ((value is null) || (value.Count == 0))
                    _qpmLimitBypassList = null;
                else if (value.Count > byte.MaxValue)
                    throw new ArgumentOutOfRangeException(nameof(QpmLimitBypassList), "Networks cannot have more than 255 entries.");
                else
                    _qpmLimitBypassList = value;
            }
        }

View on GitHub (pinned to d0484b6c1e)

Solutions

1. Set a value between 0 and 100 inclusive (e.g. 50 for 50% truncation).
2. If your config uses a 0-1 float, multiply by 100 and round before assignment.

Example fix

// before
server.QpmLimitUdpTruncationPercentage = 150; // throws

// after
server.QpmLimitUdpTruncationPercentage = 50;

int safePct = Math.Clamp(value, 0, 100);
server.QpmLimitUdpTruncationPercentage = safePct;

static bool IsValidPercentage(int p) => p >= 0 && p <= 100;

try { server.QpmLimitUdpTruncationPercentage = value; }
catch (ArgumentOutOfRangeException) { server.QpmLimitUdpTruncationPercentage = 50; }

When it happens

Trigger: Setting server.QpmLimitUdpTruncationPercentage to an int < 0 or > 100.

Common situations: Passing a fraction (e.g. 0.5) as an integer resulting in 0 unexpectedly; config file with a value like 150; misunderstanding that 0 means never truncate and 100 means always truncate.

Related errors

• QPM Prefix Limits for IPv4 cannot have more than 255 entries
• QPM Prefix Limits for IPv6 cannot have more than 255 entries
• Valid range is between 1 and 60 minutes.
• Invalid EDNS UDP payload size: valid range is 512-4096 bytes
• QPM limit IPv4 prefix valid range is between 0 and 32.

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/e704a948be5774f2. Report an issue: GitHub.