x@mxt10.test.ex is undeliverable: all relevant MX records point to non-existent hosts or (invalidly) to IP addresses **** SMTP testing session as if from host V4NET.9.8.7 **** but without any ident (RFC 1413) callback. **** This is not for real! 220 myhost.test.ex ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000 250 OK 550-Verification failed for 550-It appears that the DNS operator for mxt10.test.ex 550-has installed an invalid MX record with an IP address 550-instead of a domain name on the right hand side. 550 Sender verify failed 221 myhost.test.ex closing connection **** SMTP testing session as if from host V4NET.9.8.7 **** but without any ident (RFC 1413) callback. **** This is not for real! 220 myhost.test.ex ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000 250 OK 550-It appears that the DNS operator for mxt10.test.ex 550-has installed an invalid MX record with an IP address 550 instead of a domain name on the right hand side. 221 myhost.test.ex closing connection