private void
follow(Name name, Name oldname) {
	foundAlias = true;
	badresponse = false;
	networkerror = false;
	timedout = false;
	nxdomain = false;
	referral = false;
	iterations++;
	if (iterations >= 10 || name.equals(oldname)) {
		result = UNRECOVERABLE;
		error = "CNAME loop";
		done = true;
		return;
	}
	if (aliases == null)
		aliases = new ArrayList();
	aliases.add(oldname);
	lookup(name);
}
Sets the minimum credibility level that will be accepted when performing
the lookup.  This defaults to Credibility.NORMAL.
@param credibility The minimum credibility level.
src/main/java/core/org/xbill/DNS/Lookup.java