Well, I've obviously gotten something wrong, because I'm still getting
tons of frozen messages. Here's my ACL section, which is simply from
the default configure file with the /callout=30s added. Shouldn't the
callout be catching bad return addresses and preventing frozen messages?
######################################################################
# ACL CONFIGURATION #
# Specifies access control lists for incoming SMTP mail #
######################################################################
begin acl
# This access control list is used for every RCPT command in an incoming
# SMTP message. The tests are run in order until the address is either
# accepted or denied.
acl_check_rcpt:
deny senders = /usr/local/etc/mail/access_denied
# Accept if the source is local SMTP (i.e. not over TCP/IP). We do this by
# testing for an empty sending host field.
accept hosts = :
# Deny if the local part contains @ or % or / or | or !. These are rarely
# found in genuine local parts, but are often tried by people looking to
# circumvent relaying restrictions.
deny local_parts = ^.*[@%!/|]
# Accept mail to postmaster in any local domain, regardless of the source,
# and without verifying the sender.
accept local_parts = postmaster
domains = +local_domains
# Deny unless the sender address can be verified.
require verify = sender/callout=30s
#############################################################################
# There are no checks on DNS "black" lists because the domains that
contain
# these lists are changing all the time. However, here are two examples of
# how you could get Exim to perform a DNS black list lookup at this point.
# The first one denies, while the second just warns.
#
# deny message = rejected because $sender_host_address is in
a black list at $dnslist_domain\n$dnslist_text
# dnslists = black.list.example
#
# warn message = X-Warning: $sender_host_address is in a
black list at $dnslist_domain
# log_message = found in $dnslist_domain
# dnslists = black.list.example
#############################################################################
# Accept if the address is in a local domain, but only if the
recipient can
# be verified. Otherwise deny. The "endpass" line is the border between
# passing on to the next ACL statement (if tests above it fail) or denying
# access (if tests below it fail).
accept domains = +local_domains
endpass
# message = unknown user
verify = recipient
# Accept if the address is in a domain for which we are relaying, but
again,
# only if the recipient can be verified.
accept domains = +relay_to_domains
endpass
message = unrouteable address
verify = recipient
# If control reaches this point, the domain is neither in +local_domains
# nor in +relay_to_domains.
# Accept if the message comes from one of the hosts for which we are an
# outgoing relay. Recipient verification is omitted here, because in many
# cases the clients are dumb MUAs that don't cope well with SMTP error
# responses. If you are actually relaying out from MTAs, you should
probably
# add recipient verification here.
accept hosts = +relay_from_hosts
# Accept if the message arrived over an authenticated connection, from
# any host. Again, these messages are usually from MUAs, so recipient
# verification is omitted.
accept authenticated = *
# Reaching the end of the ACL causes a "deny", but we might as well give
# an explicit message.
deny message = relay not permitted
