diff -Nur squid-2.6.STABLE18/helpers/external_acl/ldap_group/squid_ldap_group.c squid-2.6.STABLE18-ws/helpers/external_acl/ldap_group/squid_ldap_group.c
--- squid-2.6.STABLE18/helpers/external_acl/ldap_group/squid_ldap_group.c	2006-05-22 17:42:04.000000000 -0300
+++ squid-2.6.STABLE18-ws/helpers/external_acl/ldap_group/squid_ldap_group.c	2008-03-14 21:38:24.070283506 -0200
@@ -465,9 +465,9 @@
 	}
 	rfc1738_unescape(user);
 	if (strip_nt_domain) {
-	    char *u = strchr(user, '\\');
+	    char *u = strrchr(user, '\\');
 	    if (!u)
-		u = strchr(user, '/');
+		u = strrchr(user, '/');
 	    if (u && u[1])
 		user = u + 1;
 	}