owasp-amass/amass · error

%s is not a valid IP

Error message

%s is not a valid IP

What it means

parseRange splits a scope token on '-'; if the token contains no dash it is treated as a single IP. When net.ParseIP cannot parse it, this error is returned. It means a non-range token in the IP scope is not a valid IP address.

Source

Thrown at config/scope.go:377

	}
	return nil
}

func (p *ParseIPs) appendIPs(addrs []net.IP) error {
	for _, addr := range addrs {
		*p = append(*p, addr)
	}
	return nil
}

func (p *ParseIPs) parseRange(s string) error {
	twoIPs := strings.Split(s, "-")

	// If s is not a range, try parsing it as a single IP
	if twoIPs[0] == s {
		ip := net.ParseIP(s)
		if ip == nil {
			return fmt.Errorf("%s is not a valid IP", s)
		}
		return p.appendIPs([]net.IP{ip})
	}
	start := net.ParseIP(twoIPs[0])
	end := net.ParseIP(twoIPs[1])
	if end == nil {
		num, err := strconv.Atoi(twoIPs[1])
		if err == nil {
			end = net.ParseIP(twoIPs[0])
			end[len(end)-1] = byte(num)
		}
	}
	if start == nil || end == nil {
		return fmt.Errorf("%s is not a valid IP range", s)
	}

	ips := amassnet.RangeHosts(start, end)
	if len(ips) == 0 {

View on GitHub (pinned to 79299dce87)

Solutions

1. Fix the token to be a full valid IP literal (all four octets / full IPv6)
2. If you intended a subnet, express it as an explicit range like 10.0.0.0-10.0.0.255 instead of CIDR
3. Remove hostnames from the IP scope and place them in the domain scope

Example fix

// before
scope.Set("10.0.0/24")
// after
scope.Set("10.0.0.0-10.0.0.255")

func checkSingleIP(s string) error {
	if !strings.Contains(s, "-") && net.ParseIP(s) == nil {
		return fmt.Errorf("%q is not a valid single IP", s)
	}
	return nil
}

func isSingleIP(s string) bool { return !strings.Contains(s, "-") && net.ParseIP(s) != nil }

if err := scope.Set(tok); err != nil {
	if strings.Contains(err.Error(), "is not a valid IP") {
		log.Printf("skipping invalid single IP %q", tok)
	}
}

When it happens

Trigger: Calling Set/populate with a single token (no '-') that net.ParseIP rejects: '10.0.0' (missing octet), '999.1.1.1', a hostname, or an empty/whitespace token.

Common situations: Typos in scope files, CIDR notation fed to a parser that expects 'a.b.c.d' or 'a.b.c.d-e.f.g.h' (CIDR like 10.0.0.0/24 is not handled here), or hostnames mixed into IP lists.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• %s is not a valid IP address or range
• invalid IP address in resolvers file: %s
• %s is not a valid IP range
• invalid key delimiter: %s
• brute forcing cannot be performed without DNS resolution

AI-assisted analysis of owasp-amass/amass@79299dce87 (2026-09-06). Data as JSON: /api/errors/06feeaf654568cb2. Report an issue: GitHub.