MX gateway and relay server integration for Zimbra environments

Pitbull integration with Zimbra

In environments using Zimbra, Pitbull integration works on two channels:

• Inbound: DNS MX records point to the Pitbull gateway; Rspamd-based filtering, quarantine and policy engine secure inbound traffic.
• Outbound: Outbound traffic passes through Pitbull relay via the zimbraMtaRelayHost parameter in Zimbra's Postfix layer.

Relay Server Configuration

Run zmprov ms `zmhostname` zimbraMtaRelayHost relay.pitbull.com.tr:587 via Zimbra admin CLI. This writes the relayhost parameter in Zimbra's Postfix layer.

Inbound MX Gateway

• Point domain MX records to the Pitbull gateway address (priority 10)
• Rspamd spam, phishing and malware filtering at the gateway layer
• Malicious attachment scanning via ClamAV / Avast REST
• SPF, DKIM and DMARC checks + score breakdown
• Suspicious messages isolated in quarantine; admin-approved release workflow

Outbound Relay Settings

To route outbound traffic to the Pitbull relay on Zimbra:

# Zimbra CLI (root or zimbra user)
su - zimbra
zmprov ms $(zmhostname) zimbraMtaRelayHost relay.pitbull.com.tr:587
zmprov ms $(zmhostname) zimbraMtaSmtpSaslAuthEnable yes
zmprov ms $(zmhostname) zimbraMtaSmtpSaslPasswordMaps lmdb:/opt/zimbra/conf/relay_password

# /opt/zimbra/conf/relay_password
relay.pitbull.com.tr tenant@pitbull.com.tr:RELAY_TOKEN

postmap /opt/zimbra/conf/relay_password
zmcontrol restart

This configuration passes outbound traffic through the Pitbull outbound filtering engine. SMTP Abuse Radar, per-tenant rate limits and Emergency Outbound Lockdown are activated.

Authentication

• Add Pitbull include to SPF
• Enable DKIM signing from Pitbull panel and publish DNS TXT record
• Start DMARC at p=none and monitor reports

Operational Visibility

Monitor delivery rates, reject reasons, queue status and GeoIP/ASN distribution on NOC screens. Deliver periodic security summaries to management teams with executive PDF reports.