olga@xxxxxxxxxxxxxx wrote: >> Am Do, den 24.06.2004 schrieb olga@xxxxxxxxxxxxxx um 22:47: >> >>>> 4) Should have a complete list of valid mailboxes for hosty so >>>> that if an e-mail does come in for mydomain.com on hostsx, it can >>>> reject it instead of sending a DSN back to a forged address. Thus >>>> clogging up your mail queue. I do this using LDAP queries, but you >>>> could create a list of virtual users to compensate. >> >>> Are these valid mailboxes set up in /var/spool/mail ? >> >> No! That is the local mail spool directory. As Steve said you could >> use /etc/mail/virtusertable (and it's hashed db file). >> > > Oh, ok. Then where will the mail message that comes for the domain on > Y will physically reside? Sorry if I am understanding all parts of > this clearly. > You can only have one mailbox per domain recipient. You have chosen the server where the physical mailbox lives (server x). In sendmail terms, local delivery to a mailbox is defined by adding the domain name to /etc/mail/local-host-names. But you can also have multiple mail servers accepting mail for a single domain. i.e. backup MX. So the backup MX server should not store e-mail (no entry in local-host-names), but rather relay the e-mail to the primary MX for that domain (relay-domains/mailertable). Furthermore, the backup MX server needs to know a valid list of mailboxes on the primary MX prior to relaying. Otherwise if the primary MX accepts a relay'd e-mail from the backup MX to a unknown user, it will reject it back to the sender with a DSN. Trust me, most (if not all) spam has a forged return address. So your mail queues will get clogged with undeliverable e-mails for days. Steve Cowles
