TechnitiumSoftware/DnsServer · error · ArgumentOutOfRangeException

Value must be between 1 hour and 168 hours (7 days) or 0 to

Error message

Value must be between 1 hour and 168 hours (7 days) or 0 to disable automatic update.

What it means

Thrown by the BlockListUpdateIntervalHours setter when value is < 0 or > 168. The valid range is 0 (disable automatic update) up to 168 hours (7 days); values outside that are an ArgumentOutOfRangeException.

Source

Thrown at DnsServerCore/Dns/ZoneManagers/BlockListZoneManager.cs:1088

                    }

                    if (uniqueList.Count == commentCount)
                        uniqueList = [];

                    value = uniqueList;
                }

                ApplyBlockListUrls(value);
            }
        }

        public int BlockListUpdateIntervalHours
        {
            get { return _blockListUpdateIntervalHours; }
            set
            {
                if ((value < 0) || (value > 168))
                    throw new ArgumentOutOfRangeException(nameof(BlockListUpdateIntervalHours), "Value must be between 1 hour and 168 hours (7 days) or 0 to disable automatic update.");

                _blockListUpdateIntervalHours = value;

                ApplyBlockListUpdateInterval();
            }
        }

        public bool BlockListUpdateEnabled
        { get { return _blockListUpdateTimer is not null; } }

        public DateTime BlockListLastUpdatedOn
        {
            get { return _blockListLastUpdatedOn; }
            internal set
            {
                _blockListLastUpdatedOn = value;
            }
        }

View on GitHub (pinned to d0484b6c1e)

Solutions

Pass a value in [0, 168] hours (e.g. 24 for daily, 0 to disable).
If you intended a longer interval, choose 168 (the max) and rely on manual updates beyond that.
Double-check the unit is hours, not minutes.

Example fix

// before
blockListZoneManager.BlockListUpdateIntervalHours = 240; // > 168 -> throws
// after
blockListZoneManager.BlockListUpdateIntervalHours = 168; // max = 7 days, or 0 to disable

Defensive patterns

Strategy: validation

Validate before calling

const int MaxHours = 168;
int hours = Math.Clamp(requestedHours, 0, MaxHours);
blockListZoneManager.BlockListUpdateIntervalHours = hours;

Type guard

static bool IsValidUpdateInterval(int hours) => hours >= 0 && hours <= 168;

Try / catch

try { blockListZoneManager.BlockListUpdateIntervalHours = hours; }
catch (ArgumentOutOfRangeException) { blockListZoneManager.BlockListUpdateIntervalHours = Math.Clamp(hours, 0, 168); }

Prevention

Remember the field is HOURS, not minutes or days.
Use 0 to disable automatic updates explicitly.
Clamp user-supplied values at the configuration boundary.
Document the 0..168 range in your config UI.

When it happens

Trigger: Setting the auto-update interval to a negative number; setting it above 168 (e.g. 200 hours, or treating the field as minutes/days by mistake).

Common situations: Unit confusion (passing minutes or days into an hours field); config import with a stale/out-of-range value; script computing the interval arithmetically and overflowing.

Related errors

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/f7f7f3a802c6b0b1. Report an issue: GitHub.