NEWKINGDOM FINANCIAL INC. — INTERNAL INFRASTRUCTURE

Email Server Setup

Domain: newkingdomfinancial.net  |  Platform: Digital Ocean  |  Stack: Mailcow Dockerized  |  Date: May 16, 2026

Port Architecture — How It Actually Works

PORTS IN USE — WHAT DIGITAL OCEAN BLOCKS AND WHAT IT DOESN'T
587
SMTP Submission (STARTTLS) — Client → Server
Outlook, iPhone, Thunderbird, Android send email here. Not blocked by DO.
465
SMTPS (SSL/TLS) — Client → Server
Alternative submission port with full SSL. Not blocked by DO.
993
IMAPS — Client receives / syncs mail
Email clients pull messages here. Not blocked by DO.
25
SMTP Relay — Inbound only — Other servers deliver TO you
When Gmail sends to petermartinez@newkingdomfinancial.net, Gmail's server connects here. DO allows inbound 25. Outbound 25 is what DO blocks — your server sending directly to Gmail/Outlook servers. Solved with SendGrid relay (free tier handles this).
25 out
Outbound relay — Bypassed via SendGrid
DO blocks this. We route all outbound delivery through SendGrid's free SMTP relay instead. Mailcow configures this in two fields. Free tier: 100 emails/day. Paid: $20/mo for 50,000 emails.
Bottom line

Your clients (phones, laptops, Outlook) use ports 587/465 and 993 — DO never touches those. The only workaround needed is routing outbound server delivery through SendGrid as a relay, which Mailcow handles in its config. That's it.

Step 1 — Provision the Droplet

Digital Ocean Dashboard → Create → Droplets

Droplet Specifications

SettingValue
RegionNew York 1 (or Dallas / San Francisco)
ImageUbuntu 22.04 LTS x64
PlanRegular — 4GB RAM / 2 vCPU / 80GB SSD (~$24/mo)
Hostnamemail.newkingdomfinancial.net
IPv6Enable
BackupsEnable (+$4.80/mo)
SSH KeysAdd your key for root access
After provisioning — do this first

Set Reverse DNS (PTR) in Digital Ocean

Networking → Droplets → Your Droplet → Edit rDNS → set to mail.newkingdomfinancial.net

Without a PTR record matching your hostname, Gmail and Outlook will reject your outbound mail regardless of relay settings.

Step 2 — Create Free SendGrid Relay Account

Before installing Mailcow — get your relay credentials

SendGrid setup (free, takes 5 minutes)

1. Go to sendgrid.com → Create free account

2. Settings → API Keys → Create API Key → Full Access → name it "mailcow-relay"

3. Copy the API key — you only see it once

4. Your SMTP relay credentials will be:

SettingValue
SMTP Hostsmtp.sendgrid.net
Port587
Usernameapikey (literal string)
PasswordYour SendGrid API key

These go into Mailcow's relay host settings after installation.

Step 3 — DNS Records

Add in your registrar's DNS panel. Replace [SERVER_IP] with the Droplet's public IPv4 once provisioned.

Host / NameTypeValuePriorityTTL
mailA[SERVER_IP]—3600
@MXmail.newkingdomfinancial.net103600
@TXTv=spf1 include:sendgrid.net mx ~all—3600
_dmarcTXTv=DMARC1; p=quarantine; rua=mailto:admin@newkingdomfinancial.net; fo=1—3600
dkim._domainkeyTXTGenerated after Mailcow install — copy from Mailcow admin → Configuration → ARC/DKIM Keys—3600
autoconfigA[SERVER_IP]—3600
autodiscoverA[SERVER_IP]—3600
SPF includes SendGrid

The SPF record includes include:sendgrid.net because your outbound mail flows through SendGrid's relay. This tells receiving servers that SendGrid is authorized to send on behalf of newkingdomfinancial.net.

Step 4 — Install Mailcow

SSH into the Droplet as root

1. Update and install Docker

apt update && apt upgrade -y curl -fsSL https://get.docker.com | sh apt install -y docker-compose-plugin
Step 4.2

2. Set hostname

hostnamectl set-hostname mail.newkingdomfinancial.net
Step 4.3

3. Clone and configure Mailcow

cd /opt git clone https://github.com/mailcow/mailcow-dockerized cd mailcow-dockerized ./generate_config.sh # When prompted: # Hostname: mail.newkingdomfinancial.net # Timezone: America/New_York
Step 4.4 — Critical: configure SendGrid relay BEFORE starting

4. Add relay host to mailcow.conf

nano mailcow.conf # Find and set these lines: RELAYHOST=smtp.sendgrid.net:587 RELAYHOST_USERNAME=apikey RELAYHOST_PASSWORD=[YOUR_SENDGRID_API_KEY]
Step 4.5

5. Start Mailcow

docker compose pull docker compose up -d

First start takes 3–5 minutes. Let's Encrypt SSL certificate is issued automatically for mail.newkingdomfinancial.net.

Step 5 — Create Email Accounts in Mailcow

Log in to https://mail.newkingdomfinancial.net — default admin credentials are admin / moohoo. Change the admin password immediately. Then: Mail Setup → Mailboxes → Add Mailbox.

#EmailPasswordRole
1admin@newkingdomfinancial.netP378CNRrGQqcCdS@7gSystem Admin
2webmaster@newkingdomfinancial.netaDfEt@BPCQuCCusVZHWeb Admin
3no-reply@newkingdomfinancial.netamHyK2*Qx&H#5XbYBETransactional / System
4petermartinez@newkingdomfinancial.netjPMCRtQauZRVZy5JA!Principal
5mindymartinez@newkingdomfinancial.net7G4M3H6j3SRZRrQJZ&Staff
6tabithayoung@newkingdomfinancial.nethJFy!SYYCHSQKpF&RkStaff
7davidcolon@newkingdomfinancial.netRMc5w$J7h2v*Ph5kbuStaff

Step 6 — Generate DKIM Key & Add to DNS

Mailcow Admin Panel → Configuration → ARC/DKIM Keys

Generate the DKIM key for your domain

Domain: newkingdomfinancial.net  |  Selector: dkim  |  Key Length: 2048 → Add

Copy the generated TXT value (starts with v=DKIM1; k=rsa; p=...) and add it as a DNS TXT record at dkim._domainkey.newkingdomfinancial.net

Step 7 — Email Client Settings

For Outlook, Apple Mail, iPhone, Android, Thunderbird.

Incoming Mail (IMAP)Outgoing Mail (SMTP)
Servermail.newkingdomfinancial.netmail.newkingdomfinancial.net
Port993587 (or 465)
EncryptionSSL / TLSSTARTTLS (or SSL/TLS for 465)
UsernameFull email address (e.g. petermartinez@newkingdomfinancial.net)
PasswordFrom the table above
Webmailhttps://mail.newkingdomfinancial.net

Step 8 — Verify Deliverability

CheckToolURL
MX + SPF + DKIM + DMARC all passMXToolbox SuperToolmxtoolbox.com/SuperTool.aspx
Overall spam score (target ≥ 9/10)Mail-Testermail-tester.com
PTR / reverse DNSMXToolbox Reversemxtoolbox.com/ReverseLookup.aspx
Not on any blacklistsMXToolbox Blacklistmxtoolbox.com/blacklists.aspx
DKIM signature validDKIM Validatordkimvalidator.com

Closing Checklist