{
    "mode": "man",
    "parameter": "DNSBLOG",
    "section": "8postfix",
    "url": "https://www.chedong.com/phpMan.php/man/DNSBLOG/8postfix/json",
    "generated": "2026-05-30T08:16:22Z",
    "synopsis": "dnsblog [generic Postfix daemon options]",
    "sections": {
        "NAME": {
            "content": "dnsblog - Postfix DNS allow/denylist logger\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "dnsblog [generic Postfix daemon options]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The  dnsblog(8) server implements an ad-hoc DNS allow/denylist lookup service. This may even‐\ntually be replaced by an UDP client that is built directly into the postscreen(8) server.\n",
            "subsections": []
        },
        "PROTOCOL": {
            "content": "With each connection, the dnsblog(8) server receives a DNS allow/denylist domain name, an  IP\naddress, and an ID.  If the IP address is listed under the DNS allow/denylist, the dnsblog(8)\nserver logs the match and replies with the query arguments plus an address list with the  re‐\nsulting  IP addresses, separated by whitespace, and the reply TTL.  Otherwise it replies with\nthe query arguments plus an empty address list and the reply TTL; the  reply  TTL  is  -1  if\nthere  is no reply, or a negative reply that contains no SOA record.  Finally, the dnsblog(8)\nserver closes the connection.\n",
            "subsections": []
        },
        "DIAGNOSTICS": {
            "content": "Problems and transactions are logged to syslogd(8) or postlogd(8).\n",
            "subsections": []
        },
        "CONFIGURATION PARAMETERS": {
            "content": "Changes to main.cf are picked up automatically, as dnsblog(8) processes run for only  a  lim‐\nited amount of time. Use the command \"postfix reload\" to speed up a change.\n\nThe  text below provides only a parameter summary. See postconf(5) for more details including\nexamples.\n\nconfigdirectory (see 'postconf -d' output)\nThe default location of the Postfix main.cf and master.cf configuration files.\n\ndaemontimeout (18000s)\nHow much time a Postfix daemon process may take to handle a request before it is  ter‐\nminated by a built-in watchdog timer.\n\npostscreendnsblsites (empty)\nOptional list of DNS allow/denylist domains, filters and weight factors.\n\nipctimeout (3600s)\nThe  time  limit  for  sending or receiving information over an internal communication\nchannel.\n\nprocessid (read-only)\nThe process ID of a Postfix command or daemon process.\n\nprocessname (read-only)\nThe process name of a Postfix command or daemon process.\n\nqueuedirectory (see 'postconf -d' output)\nThe location of the Postfix top-level queue directory.\n\nsyslogfacility (mail)\nThe syslog facility of Postfix logging.\n\nsyslogname (see 'postconf -d' output)\nA prefix that is prepended to the process name in syslog records, so that,  for  exam‐\nple, \"smtpd\" becomes \"prefix/smtpd\".\n\nAvailable in Postfix 3.3 and later:\n\nservicename (read-only)\nThe master.cf service name of a Postfix daemon process.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "smtpd(8), Postfix SMTP server\npostconf(5), configuration parameters\npostlogd(8), Postfix logging\nsyslogd(8), system logging\n",
            "subsections": []
        },
        "LICENSE": {
            "content": "The Secure Mailer license must be distributed with this software.\n",
            "subsections": []
        },
        "HISTORY": {
            "content": "This service was introduced with Postfix version 2.8.\n\nAUTHOR(S)\nWietse Venema\nIBM T.J. Watson Research\nP.O. Box 704\nYorktown Heights, NY 10598, USA\n\nWietse Venema\nGoogle, Inc.\n111 8th Avenue\nNew York, NY 10011, USA\n\n\n\nDNSBLOG(8postfix)",
            "subsections": []
        }
    },
    "summary": "dnsblog - Postfix DNS allow/denylist logger",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "smtpd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/smtpd/8/json"
        },
        {
            "name": "postconf",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/postconf/5/json"
        },
        {
            "name": "postlogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/postlogd/8/json"
        },
        {
            "name": "syslogd",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/syslogd/8/json"
        }
    ]
}