How much does it cost to run Mailcow?

The software is free. You pay for hosting: a VPS with 2GB+ RAM and port 25 open costs $4.90-$9.90/month (Hetzner CX21 or similar). At 50,000 emails/month, that's $5/month vs $75/month on Mailgun. At 500,000 emails/month, it's $10-20/month vs $275/month on Mailgun.

Is Mailcow good for sending marketing email?

Mailcow can handle marketing email but it requires proper IP warmup, list management, and sending throttling that you manage yourself. For high-volume marketing, consider Mailcow for SMTP relay only and use your marketing platform for campaign management.

Can I connect Mailcow to GoHighLevel?

Yes. Use Mailcow's SMTP credentials in GoHighLevel's custom SMTP settings. Host: your Mailcow server hostname, Port: 587, Username/Password: a Mailcow mailbox account. All email from GHL routes through your self-hosted infrastructure.

Which VPS providers allow port 25 for email?

Hetzner, OVHcloud, and Vultr allow port 25 on most plans. DigitalOcean blocks port 25 by default but you can request it be opened (not guaranteed). AWS EC2 blocks port 25 — you need to request removal of the restriction. Avoid providers that permanently block port 25.

Is self-hosted email reliable enough for business?

Yes, with proper setup and monitoring. Mailcow includes automatic updates, built-in antispam (Rspamd), virus scanning (ClamAV), and a web admin panel. The risk is unmanaged maintenance — if your server goes down at 2am, you're the one fixing it.

Mailcow Complete Setup Guide: Self-Hosted Email Server (2026)

Why Self-Host Email

You're paying Mailgun $75/month to send 50,000 emails. Or SendGrid $90/month. Or $250/month at higher volumes.

Mailcow on a $5 VPS handles the same volume. That's $840/year saved at 50K/month. At 500K/month, you're saving $3,000+/year.

But cost isn't the only reason. Self-hosted email gives you:

Full control over your sending reputation
Complete visibility into delivery logs
No shared IP risk (your IP, your reputation, period)
No ESP rate limits or throttling policies
Data ownership (your email data stays on your server)

The trade-off: you manage the infrastructure. Mailcow makes this dramatically easier than bare Postfix, but it's still your responsibility.

Requirements

VPS: 2GB RAM minimum (4GB recommended for 100K+/month)
OS: Ubuntu 22.04 or Debian 12
Port 25 open (check with your VPS provider before purchasing)
Dedicated IPv4 with clean reputation (check blacklists before deploying)
Domain name with full DNS control
PTR record (reverse DNS) — must match your mail server hostname

Recommended VPS Providers

Provider	Plan	RAM	Price	Port 25
Hetzner CX21	Cloud	2GB	€4.90/mo	Open
Hetzner CX31	Cloud	4GB	€8.90/mo	Open
OVHcloud VPS	Starter	2GB	~$6/mo	Open
Vultr	Cloud Compute	2GB	$12/mo	Open

Hetzner is the go-to for self-hosted email. Cheap, reliable, port 25 open by default, and PTR records configurable in the dashboard. See our VPS comparison for more options.

Step 1: Server Setup

SSH into your VPS and prepare the system:

apt update && apt upgrade -y
apt install curl git -y

Set the hostname to match your mail server:

hostnamectl set-hostname mail.yourdomain.com

Step 2: Install Mailcow

cd /opt
git clone https://github.com/mailcow/mailcow-dockerized
cd mailcow-dockerized
./generate_config.sh

The script asks for your mail server hostname (e.g., mail.yourdomain.com) and timezone. It generates mailcow.conf.

Start Mailcow:

docker compose up -d

First startup downloads containers and initializes. Takes 5-10 minutes. Access the admin panel at https://mail.yourdomain.com (default credentials: admin / moohoo).

Change the admin password immediately.

Step 3: DNS Configuration

This is the critical step. Configure these DNS records on your domain:

MX Record

yourdomain.com    MX    10    mail.yourdomain.com

A Record

mail.yourdomain.com    A    YOUR_SERVER_IP

SPF Record

yourdomain.com    TXT    v=spf1 a mx ip4:YOUR_SERVER_IP -all

DKIM

Mailcow generates DKIM keys automatically. In the admin panel: Configuration → Domains → your domain → DKIM. Copy the generated TXT record and add it to DNS:

dkim._domainkey.yourdomain.com    TXT    v=DKIM1; k=rsa; p=YOUR_PUBLIC_KEY

DMARC

_dmarc.yourdomain.com    TXT    v=DMARC1; p=none; rua=mailto:[email protected]

PTR Record (Reverse DNS)

In your VPS provider's dashboard, set the PTR record for your IP to mail.yourdomain.com. This is critical — missing PTR records cause immediate rejection by many ISPs.

Autodiscover (Optional but recommended)

autodiscover.yourdomain.com    CNAME    mail.yourdomain.com
autoconfig.yourdomain.com     CNAME    mail.yourdomain.com

Step 4: Testing

After DNS propagates (1-24 hours):

Send a test email from Mailcow's webmail to a Gmail and Outlook address
Check headers — SPF, DKIM, and DMARC should all show pass
Run Mail-Tester — send to their test address, aim for 9+/10
Check blacklists — use MXToolbox to verify your IP isn't listed

Step 5: Connecting to GoHighLevel

In GoHighLevel → Settings → Email Services → Add SMTP:

Host: mail.yourdomain.com
Port: 587
Username: a Mailcow mailbox (e.g., [email protected])
Password: that mailbox's password
Encryption: STARTTLS

Create a dedicated mailbox in Mailcow specifically for SMTP relay. Don't use your personal mailbox.

Cost Comparison

Volume/Month	Mailgun	SendGrid	Self-Hosted (Mailcow)	Annual Savings
10,000	$35	$20	$5	$180-$360
50,000	$75	$90	$5-10	$780-$1,020
100,000	$175	$135	$10	$1,500-$1,980
500,000	$275	$249	$20	$2,748-$3,060

Practitioner note: Mailcow is not set-and-forget. Plan for 1-2 hours/month of maintenance: updating Docker containers, checking logs, monitoring reputation. If you're not comfortable with a Linux terminal, self-hosting isn't for you.

Practitioner note: Always check your VPS IP against blacklists BEFORE deploying. Some VPS IPs are recycled from previous tenants who were spammers. If the IP is dirty, request a new one from your provider.

Practitioner note: For agencies running 5+ client domains on Mailcow, use Mailcow's multi-domain support with separate DKIM keys per domain. Don't share a single SMTP credential across clients.

If the setup and maintenance is what's holding you back, schedule a consultation — I set up and manage self-hosted SMTP infrastructure for clients who want the cost savings without the technical overhead.

Sources

v1.0 · March 2026