fatedier/frp · error

range number is invalid

Error message

range number is invalid

What it means

Returned by ParseRangeNumbers when a range token's bounds parse successfully but maxValue < minValue, e.g. "2000-1000". This variant carries no %v detail because it is a semantic (not syntactic) failure: the range is inverted. Expansion of an inverted range is rejected rather than silently producing an empty set.

Source

Thrown at pkg/util/util/util.go:99

			if errRet != nil {
				err = fmt.Errorf("range number is invalid, %v", errRet)
				return
			}
			numbers = append(numbers, singleNum)
		case 2:
			// range numbers
			minValue, errRet := strconv.ParseInt(strings.TrimSpace(numArray[0]), 10, 64)
			if errRet != nil {
				err = fmt.Errorf("range number is invalid, %v", errRet)
				return
			}
			maxValue, errRet := strconv.ParseInt(strings.TrimSpace(numArray[1]), 10, 64)
			if errRet != nil {
				err = fmt.Errorf("range number is invalid, %v", errRet)
				return
			}
			if maxValue < minValue {
				err = fmt.Errorf("range number is invalid")
				return
			}
			for i := minValue; i <= maxValue; i++ {
				numbers = append(numbers, i)
			}
		default:
			err = fmt.Errorf("range number is invalid")
			return
		}
	}
	return
}

func GenerateResponseErrorString(summary string, err error, detailed bool) string {
	if detailed {
		return err.Error()
	}
	return summary

View on GitHub (pinned to 6c8a8d0a97)

Solutions

1. Swap the bounds so the smaller number comes first: "8000-9000"
2. Prefer explicit single ports if you only need a few, avoiding long ranges
3. Verify with frpc verify before restarting the client

Example fix

# before
ports = "9100-9000"

# after
ports = "9000-9100"

func rangeOrderValid(s string) bool {
    for _, tok := range strings.Split(s, ",") {
        parts := strings.Split(strings.TrimSpace(tok), "-")
        if len(parts) == 2 {
            lo, e1 := strconv.ParseInt(strings.TrimSpace(parts[0]), 10, 64)
            hi, e2 := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64)
            if e1 != nil || e2 != nil || hi < lo { return false }
        }
    }
    return true
}

When it happens

Trigger: Any dash-separated token where the left number is greater than the right: "9000-8000". Config fields for port ranges in frpc/frps parsed by ParseRangeNumbers.

Common situations: Reordering ports while editing config and swapping the bounds; auto-generated range templates filled in the wrong order.

Related errors

• range number is invalid, %v
• auth.oidc.clientID is required; auth.oidc.tokenEndpointURL i
• localAddr is required
• localPath is required
• unixPath is required

AI-assisted analysis of fatedier/frp@6c8a8d0a97 (2026-08-15). Data as JSON: /api/errors/f4d60a76cd906f59. Report an issue: GitHub.