Google スプレッドシートで DNS を照会する

function NSLookup(type, domain, useCache = false, minCacheTTL = 30) {
	// --- Parameter validation ---
	if (typeof type == "undefined") {
		throw new Error("Missing parameter 1 dns type");
	}

	if (typeof domain == "undefined") {
		throw new Error("Missing parameter 2 domain name");
	}

	if (typeof useCache != "boolean") {
		throw new Error("Only boolean values allowed in 3 use cache");
	}

	if (typeof minCacheTTL != "number") {
		throw new Error("Only numeric values allowed in 4 min cache ttl");
	}

	type = type.toUpperCase();
	domain = domain.toLowerCase();

	// --- Optional caching layer (uses Google Apps Script CacheService) ---
	let cache = null;
	if (useCache) {
		// Cache key and hash
		cacheKey = domain + "@" + type;
		cacheHash = Utilities.base64Encode(cacheKey);
		cacheBinKey = "nslookup-result-" + cacheHash;

		cache = CacheService.getScriptCache();
		const cachedResult = cache.get(cacheBinKey);
		if (cachedResult != null) {
			return cachedResult;
		}
	}

	// --- DNS-over-HTTPS query to Cloudflare's 1.1.1.1 resolver ---
	const url =
		"https://cloudflare-dns.com/dns-query?name=" +
		encodeURIComponent(domain) +
		"&type=" +
		encodeURIComponent(type);
	const options = {
		muteHttpExceptions: true,
		headers: {
			accept: "application/dns-json",
		},
	};

	const result = UrlFetchApp.fetch(url, options);
	const rc = result.getResponseCode();
	const resultText = result.getContentText();

	if (rc !== 200) {
		throw new Error(rc);
	}

	// --- Standard DNS response codes ---
	const errors = [
		{ name: "NoError", description: "No Error" }, // 0
		{ name: "FormErr", description: "Format Error" }, // 1
		{ name: "ServFail", description: "Server Failure" }, // 2
		{ name: "NXDomain", description: "Non-Existent Domain" }, // 3
		{ name: "NotImp", description: "Not Implemented" }, // 4
		{ name: "Refused", description: "Query Refused" }, // 5
		{ name: "YXDomain", description: "Name Exists when it should not" }, // 6
		{ name: "YXRRSet", description: "RR Set Exists when it should not" }, // 7
		{ name: "NXRRSet", description: "RR Set that should exist does not" }, // 8
		{ name: "NotAuth", description: "Not Authorized" }, // 9
	];

	const response = JSON.parse(resultText);

	if (response.Status !== 0) {
		return errors[response.Status].name;
	}

	// --- Extract answer records and determine cache TTL ---
	const outputData = [];
	let cacheTTL = 0;

	for (const i in response.Answer) {
		outputData.push(response.Answer[i].data);
		const ttl = response.Answer[i].TTL;
		cacheTTL = Math.min(cacheTTL || ttl, ttl);
	}

	const outputString = outputData.join(",");

	if (useCache) {
		cache.put(cacheBinKey, outputString, Math.max(cacheTTL, minCacheTTL));
	}

	return outputString;
}

=NSLookup(B1, B2)

=NSLookup(B1; B2)

198.41.214.162, 198.41.215.162