Spam delivery failures with a twist - please help

Question

Just like many others we receive undelivered spam message notifications (non-existent users in from and reply-to).
The issue that I having is that at one point in time (Mac OS X 10.3) the recipient for undeliverable mail was setup to deliver to the [email protected] (in the serveradmin app). Not a smart move but that was the person taking care of things then.
Meanwhile the Server upgraded to tiger and that address was changed to [email protected]
While I am unclear if there even has to be an entry in serverdamin for postmaster (since that's the default setting anyway), the webmaster mailbox still receives all emails and I can't stop that.
I have looked at the postfix settings (main.cf) but can't find where that record would be.
Can anyone help? Thanks!
Xserve's, Powerbooks   Mac OS X (10.4.4)  

Answer 1

Thanks for the quick respone!
I did look in the alias file as well and there is no reference to webmaster.
Here is the postconf output:
alias_maps = hash:/etc/aliases
always_bcc =
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
debugpeerlevel = 2
enableserveroptions = yes
inet_interfaces = all
localrecipientmaps =
luser_relay = postmaster
mail_owner = postfix
mailbox_transport = cyrus
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
mapsrbldomains = relays.ordb.org,opm.blitzed.org,bl.spamcop.net
messagesizelimit = 0
mydestination = $myhostname,localhost.$mydomain
mydomain_fallback = localhost
myhostname = mydomain.com
mynetworks = 127.0.0.1/32
mynetworks_style = host
newaliases_path = /usr/bin/newaliases
queue_directory = /private/var/spool/postfix
readme_directory = /usr/share/doc/postfix
relayhost =
sample_directory = /usr/share/doc/postfix/examples
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtpd_banner = $myhostname ESMTP SMTP
smtpdclientrestrictions = permit_mynetworks rejectrblclient relays.ordb.org rejectrblclient opm.blitzed.org rejectrblclient bl.spamcop.net rejectrblclient sbl-xbl.spamhaus.org permit
smtpdenforcetls = no
smtpdpw_server_securityoptions = cram-md5
smtpdrecipientrestrictions = permitsasl_authenticated,permit_mynetworks,reject_unauthdestination,permit
smtpdsasl_authenable = yes
smtpdtls_certfile = /etc/certificates/Default.crt
smtpdtls_keyfile = /etc/certificates/Default.key
smtpdtlsloglevel = 0
smtpduse_pwserver = yes
smtpdusetls = no
unknownlocal_recipient_rejectcode = 550
virtualmailboxdomains = hash:/etc/postfix/virtual_domains
virtual_transport = lmtp:unix:/var/imap/socket/lmtp