Hopefully the network operations group of peach.ease.lsoft.com are well aware that their SENDMAIL isn't as well as any other IP-based service. Since you have indicated that this appears to be a routing problem Going to the WHOIS db at Internic and entering the following command: whois net 163.179 produces: NETCOM Online Communications Services (NET-NET-NETCOM) 3031 Tisch Way San Jose, CA 95128 Netname: NET-NETCOM Netnumber: 163.179.0.0 Coordinator: Hood, Robert (RH505) [log in to unmask] (408) 983-1510 Of course e-mail to them might have difficulties too depending upon, among others, which of the 9 MX it delivers to and if the are affected by the routing loop. BTW, thank you for doing the TRACEROUTE -- I was unaware that that LISTSERV-peered host net was unavailable (though I knew that mail through there was having difficulties). -- co-owner: INFOSYS, TQM-L, CPARK-L, ERAPPA-L, JANITORS, LDBASE-L, et -L URL:mailto:[log in to unmask] "This e-mail msg rated NC-17 -- age-proof req."