I've had it up and running now for about a month, and nothing gets blacklisted, and it hasn't cut down on any spam. Here's the config file:

########################################################################
### FILE: /etc/greylistd/config
### PURPOSE: Configuration settings for the "greylistd(8)" daemon
########################################################################

[timeouts]
# Initial delay before previously unknown triplets are allowed to pass
# Default is 10 minutes = 600 seconds
retryMin = 3600

# Lifetime of triplets that have not been retried after initial delay
# Default is 8 hours = 28800 seconds
retryMax = 28800

# Lifetime of auto-whitelisted triplets that have allowed mail to pass
# Default is 60 days = 5,184,000 seconds
expire = 5184000


[socket]
# Path to the UNIX domain socket on which greylistd will listen.
# The parent directory must be writable by the user running 'greylistd'.
# Default path is "/var/run/greylistd/socket".
path = /var/run/greylistd/socket

# UNIX filemode of that socket. See "chmod(1)" for the meaning of this.
# Default mode is 0660.
mode = 0660


[data]
# Update interval -- save data to the filesystem if if has been more
# than this many seconds (default 600) since the last save.
update = 600

# Path to the file containing the current state of each data item (triplet),
# along with some general statistics.
# Default is "/var/lib/greylistd/states".
statefile = /var/lib/greylistd/states

# Path to the file that will contain the original, unhashed data for the
# "list" command. Default is "/var/lib/greylistd/triplets".
tripletfile = /var/lib/greylistd/triplets

# Whether or not to retain unhashed triplets, for the "list" command.
# Default is "true"
savetriplets = true

# Whether check/update also checks for an whitelist entry, which only
# contains the first word of the triplet, that is the IP address usually.
# If set to true, you can also insert general IP addresses/networks into the
# whitelist, without email addresses.
singlecheck = false

# Whether update only inserts the first word of the triplet into the
# whitelist, that is the IP address usually. Meant to be used in
# conjunction with singlecheck = true.
singleupdate = false

########## End greylist config #######################

I even emailed the author (since he published his email address and invited users with question to do so), but, of course, got no reply. I haven't seen this in any forums, and am wondering if anyone is using it.

TIA,
-- anw --

Greylisting is quite a common tool that forms part of the defense against spam. But to have it do any good, it must be integrated with the mail-receiving daemon. You don't say which mail-handling system you use, but it would be a good idea to check your /var/log/maillog (or equivalent) to see if there are ever any uses of the greylisting facility that you have installed. It is entirely possible that you have a correctly-installed greylist daemon that is not being referenced.

I use Postfix, and integration with that system is pretty straightforward; the process is described here. Other mailer daemons will have different integration procedures, but the scheme is the same: all incoming mail is routed through the greylistd daemon, which returns either a yea or a nay. The mailer daemon then either accepts or rejects the incoming mail connection. When I first installed this daemon, about 75% of my incoming mail was rejected (essentially all spam). So you should definitely see a difference if it is working.

BTW, if you are not also using the Spamhaus blacklisting servers, I recommend them as well. I have had almost no trouble with false hits, their lists of known spammer addresses seem to be kept quite up-to-date.

Hey, thanks for the reply! Sorry I've been off-line for a while.

I use exim4,and I can see it grey listing in the log files, but the blacklist remains empty. I've adjusted the time for retries from the default 10 mins to 60 mins, no change. Here's what the statistics part of the /var/lib/greylistd/states file says:
Note black = 0.

And, yes, I've just recently started using Spamhaus, and have found as you that it works very well. The config how-to I used also had several others listed, and, as near as I can tell, they are all pretty good.