# info > DNSBLOG

---
type: CommandReference
command: dnsblog
mode: man
section: 8postfix
source: man-pages
---

## Quick Reference

- Start dnsblog daemon: `dnsblog`
- Use alternate configuration directory: `dnsblog -c /etc/postfix-custom`
- Increase verbosity: `dnsblog -v`
- Set DNS allow/denylist sites in `main.cf`: `postscreen_dnsbl_sites = zen.spamhaus.org*2, b.barracudacentral.org`
- Reload Postfix to apply changes: `postfix reload`
- View dnsblog log entries: `tail -f /var/log/maillog | grep dnsblog`

## Name

Postfix DNS allow/denylist logger

## Synopsis

`dnsblog [generic Postfix daemon options]`

## Options

### Command-line options

- `-c` *config_directory* — Override the default configuration directory.
- `-v` — Increase verbose logging.
- `-D` — Enable debugging output.

### Configuration parameters

- `postscreen_dnsbl_sites` — DNS allow/denylist domains, filters, and weight factors (e.g., `zen.spamhaus.org*2`). Default: empty.
- `daemon_timeout` (18000s) — Request handling time limit; process is terminated by watchdog if exceeded.
- `ipc_timeout` (3600s) — Timeout for internal communication channels.
- `syslog_facility` (mail) — Facility used for syslog logging.
- `syslog_name` — Prefix added to the process name in syslog records (e.g., `prefix/smtpd`).
- `config_directory` — Path to Postfix configuration files (`main.cf`, `master.cf`).
- `queue_directory` — Top-level queue directory.
- `process_id` (read‑only) — Process ID of the daemon.
- `process_name` (read‑only) — Process name.
- `service_name` (read‑only, Postfix ≥ 3.3) — `master.cf` service name of the daemon.

## See Also

- [smtpd(8)](http://localhost/phpMan.php/man/smtpd/8/markdown) — Postfix SMTP server
- [postconf(5)](http://localhost/phpMan.php/man/postconf/5/markdown) — Configuration parameters
- [postlogd(8)](http://localhost/phpMan.php/man/postlogd/8/markdown) — Postfix logging
- [syslogd(8)](http://localhost/phpMan.php/man/syslogd/8/markdown) — System logging