fix: allow underscores in domain labels

src/client.tsmodified+2-2

Changes to src/client.ts

		⋯40 linesShow the 40 lines above this hunk@@ -41,7 +41,7 @@ export class DnsClient {
41	41	* - Start/end dots
42	42	* - Overall length (max 253 characters)
43	43	* - Label length (max 63 characters)
44		- * - Valid characters (a-z, 0-9, -)
	44	+ * - Valid characters (a-z, 0-9, -, _)
45	45	*
46	46	* @param domain - The domain name to validate
47	47	* @throws {Error} If the domain name is invalid
		⋯22 linesShow the 22 lines above this hunk@@ -70,7 +70,7 @@ export class DnsClient {
70	70	}
71	71
72	72	// Check label characters
73		- if (!/^[a-z0-9-]+$/i.test(label)) {
	73	+ if (!/^[a-z0-9_-]+$/i.test(label)) {
74	74	throw new Error(`Invalid characters in domain label: ${label}`)
75	75	}
76	76	}

test/dnsx.test.tsmodified+17-0

Changes to test/dnsx.test.ts

		⋯186 linesShow the 186 lines above this hunk@@ -187,6 +187,23 @@ describe('DnsClient', () => {
187	187	})).toThrow()
188	188	})
189	189
	190	+ it('should accept underscores in domain labels (DKIM, DMARC, SRV)', () => {
	191	+ expect(() => new DnsClient({
	192	+ domains: ['selector1._domainkey.example.com'],
	193	+ type: 'TXT',
	194	+ })).not.toThrow()
	195	+
	196	+ expect(() => new DnsClient({
	197	+ domains: ['_dmarc.example.com'],
	198	+ type: 'TXT',
	199	+ })).not.toThrow()
	200	+
	201	+ expect(() => new DnsClient({
	202	+ domains: ['_sip._tcp.example.com'],
	203	+ type: 'SRV',
	204	+ })).not.toThrow()
	205	+ })
	206	+
190	207	it('should handle invalid record types', () => {
191	208	expect(() => new DnsClient({
192	209	domains: ['example.com'],