MX gateway and relay server integration for Carbonio environments

Pitbull MX gateway for Carbonio (Commercial, Linux) mail servers: inbound filtering, quarantine and outbound relay. Outbound traffic passes through Pitbull via relayhost on the Zextras Carbonio Postfix layer.

Carbonio · Relay MX + Relay Server
Inbound MX ROUTED
Relay AKTİF
Filter RSPAMD
Abuse OBSERVE
Carbonio Relay MX Gateway Rspamd NOC
Linux
Platform
Commercial
License
MX+Relay
Gateway model
KVKK
Local processing

Integration challenges

Pitbull solves mail security on this platform with the MX gateway model.

Limited native filtering

Carbonio default spam protection is insufficient against advanced phishing and BEC attacks.

Outbound blind spot

Without relay configuration, outbound spam and abuse detection is delayed; IP reputation drops.

Missing central visibility

Hard to monitor traffic, quarantine and reject reasons from one point.

Scattered policy

Managing SPF/DKIM/DMARC and quarantine policies per server increases error risk.

Pitbull integration with Carbonio

In environments using Carbonio, 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 via relayhost on the Zextras Carbonio Postfix layer.

Relay Server Configuration

Carbonio is Zimbra-based and uses Postfix. Set relayhost = [relay.pitbull.com.tr]:587 via carbonio prov or Postfix main.cf. Authenticate with SASL password maps.

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 Carbonio:

# Carbonio / Postfix
relayhost = [relay.pitbull.com.tr]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = lmdb:/opt/zextras/conf/relay_password
smtp_tls_security_level = encrypt

# /opt/zextras/conf/relay_password
[relay.pitbull.com.tr]:587 tenant@pitbull.com.tr:RELAY_TOKEN

postmap /opt/zextras/conf/relay_password
postfix reload

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.

Illustrated setup guide

Pitbull integration on this platform is completed in 4 visual steps.

Gateway flow diagram
MX Gateway
1

MX Gateway

Point DNS MX to the Pitbull gateway address.

SPF · DKIM · DMARC
2

SPF · DKIM · DMARC

Add authentication DNS records.

Outbound Relay
3

Outbound Relay

Set Pitbull relay as smarthost / relayhost.

NOC Verification
4

NOC Verification

Send a test email and verify in the NOC panel.

Setup steps

  1. 1 Point DNS MX records to the Pitbull gateway address (priority 10).
  2. 2 Add Pitbull include to SPF; generate DKIM TXT from panel and add to DNS.
  3. 3 Set the Pitbull relay address in Carbonio relay/smarthost settings.
  4. 4 Send a test email and verify inbound/outbound traffic in the NOC panel.
  5. 5 Start DMARC at p=none and monitor aggregate reports.