relay.srv.gc.ca has one IP number , which also has a corresponding reverse pointer. gc.ca, agr.ca, cdc.ca, grc.ca, schl.ca and at least 100 other hosts use this as a nameserver. srv.gc.ca is a domain controlled by four nameservers. All of them are on different IP networks. Incoming mail for srv.gc.ca is handled by one mailserver at srv.gc.ca themselves. relay.srv.gc.ca is hosted on a server in Canada.