if str(filter_s).find('(dnsAlias=') != -1:

	filter_s = univention.admin.handlers.dns.alias.lookup_alias_filter(lo, filter_s)

		filter_s = univention.admin.handlers.dns.alias.lookup_alias_filter(lo, filter_s)

		if filter_s:

			return lookup_filter(filter_s, lo)

		else:

			return None

def lookup(co, lo, filter_s, base='', superordinate=None, scope="sub", unique=False, required=False, timeout=-1, sizelimit=0):

def _lookup_filter(filter_s=None, lo=None):  # don't expose as lookup_filter because the superordinate argument is missing!

	_re = re.compile('(.*)\(dnsAlias=([^=,]+)\)(.*)')

	alias_pattern = re.compile('(?:^|\()dnsAlias=([^)]+)($|\))', flags=re.I)

	match = _re.match(str(filter_s))

	filterlist = []

	def _replace_alias_filter(match):

	if match:

		alias_filter = _lookup_filter('name=%s' % match.group(1), lo)

		filter_p = univention.admin.filter.parse('name=%s' % match.group(2))

		univention.admin.filter.walk(filter_p, univention.admin.mapping.mapRewrite, arg=mapping)  # map property to ldap attribute

		alias_filter = univention.admin.filter.conjunction('&', [		# from dns/alias.lookup

			univention.admin.filter.expression('objectClass', 'dNSZone'),

			univention.admin.filter.conjunction('!', [univention.admin.filter.expression('relativeDomainName', '@')]),

			univention.admin.filter.conjunction('!', [univention.admin.filter.expression('zoneName', '*.in-addr.arpa')]),

			univention.admin.filter.expression('CNAMERecord', '*')

		])

		alias_filter.expressions.append(filter_p)

		alias_base = unicode(lo.base)					# std dns container might be a better choice

		alias_base = unicode(lo.base)  # standard dns container might be a better choice

		for dn, attrs in lo.search(base=alias_base, scope='sub', filter=alias_filter_s, attr=['cNAMERecord']):

			cname = attrs['cNAMERecord'][0]

		unmatchable_filter = '(&(cn=NOT)(!(cn=NOT)))'  # if no computers for aliases found, return an impossible filter!

			cn_filter = filter_format('(cn=%s)', [cname.split('.', 1)[0]])

		alias_replaced = ''.join(set(filter_format('(cn=%s)', [attrs['cNAMERecord'][0].split('.', 1)[0]]) for dn, attrs in lo.search(base=alias_base, scope='sub', filter=alias_filter_s, attr=['cNAMERecord'])))

			if cn_filter not in filterlist:

		return '(|%s)' % (alias_replaced,) if alias_replaced else unmatchable_filter

				filterlist.append(cn_filter)

		if len(filterlist) > 0:

	return alias_pattern.sub(_replace_alias_filter, str(filter_s))

			return match.group(1) + '(|' + string.join(filterlist, '') + ')' + match.group(3)

		else:

			return ''

	else:

		return filter_s