IP Spam Filter

This page explains the IP Spam Filter feature in GoAdmio. It lets you block incoming email from specific IP addresses at the server level — and lets each hosting account add its own blocked IPs, scoped to that account.

Location: Admin Panel → Email → IP Spam Filter
Location (User Panel): Email → IP Spam Filter

Overview

The IP Spam Filter blocks email at the SMTP level based on the connecting IP address. When a sender connects from a blocked IP, GoAdmio rejects the message before it is accepted — the message never reaches the mailbox, the spam filter, or the AI contact detection.

Unlike content-based spam filters, the IP Spam Filter operates on who is sending, not what is sent. This makes it fast, deterministic, and very effective against known spam sources, compromised servers, and repeat offenders.

GoAdmio's IP Spam Filter works at two levels:

| Level | Managed by | Scope |
|---|---|---|
| Server-wide blocklist | Server administrator (root) | Blocks the IP for all domains on the server |
| Per-account blocklist | Each hosting account owner | Blocks the IP for that account's domains only |

This two-tier design lets the host protect the whole server while giving each customer control over their own inbox.

> Note: The IP Spam Filter is different from IP Blocker, which blocks web traffic (HTTP/HTTPS) from an IP. IP Spam Filter blocks email (SMTP) from an IP. Use both together for full coverage.

How It Works

When an external mail server connects to deliver a message:

1. GoAdmio reads the connecting IP from the SMTP session.
2. It checks the IP against:

1. If the IP is on either list, the message is rejected at SMTP time with a policy error.
2. If the IP is not blocked, the message proceeds to normal spam filtering and delivery.

Server-Wide Blocklist (Admin)

The server administrator can block IPs for the entire server. This is the right place to block:

• Known spam sources and open relays
• Compromised servers sending spam to your users
• Abusive senders reported by multiple customers
• IPs from regions you do not do business with (in combination with Country Whitelist)

How to Add a Server-Wide Block

1. Log in to the GoAdmio Admin Panel.
2. Navigate to Email → IP Spam Filter.
3. Under the Server section, add the IP address (or CIDR range).
4. Optionally add a reason (e.g., "Spam source — reported by 3 customers").
5. Click Add (or Block).

Managing the Server Blocklist

| Action | How |
|---|---|
| View | The Server section lists all blocked IPs |
| Search | Filter the list by IP or reason |
| Remove | Click Delete next to the IP, then confirm |
| Bulk import | Paste a list of IPs or CIDR ranges (one per line) if supported |

> Warning: Blocking an IP at the server level affects all customers. Before blocking, confirm the IP is not a shared mail provider (e.g., Gmail, Microsoft 365, Amazon SES) that legitimate customers rely on. If you must block a shared provider, consider a per-account block instead.

Per-Account Blocklist (User Panel)

Each hosting account can block IPs for its own domains only. This lets customers take action against spam without asking the host, and without affecting other customers.

How to Add an Account-Level Block

Via the User Panel:

1. Log in to the User Panel.
2. Navigate to Email → IP Spam Filter.
3. Enter the IP address to block.
4. Optionally add a reason.
5. Click Add (or Block).

1. Log in to the Admin Panel.
2. Navigate to Email → IP Spam Filter.
3. Select the account or domain.
4. Add the IP to that account's blocklist.

Managing the Account Blocklist

| Action | How |
|---|---|
| View | The account section lists the account's blocked IPs |
| Search | Filter by IP or reason |
| Remove | Click Delete next to the IP |
| Clear all | Some versions provide a "Clear all" action for the account |

> Tip: Account-level blocks are the safest option for customers. They take effect for that account only and cannot disrupt other customers' mail.

CIDR Ranges

Both the server-wide and per-account blocklists accept CIDR notation for blocking an entire range of IPs. This is useful for:

• Blocking a spam-hosting provider's IP range
• Blocking a specific cloud region known for abuse
• Blocking an entire netblock after repeated incidents

| Entry | Effect |
|---|---|
| 203.0.113.45 | Blocks a single IP |
| 203.0.113.0/24 | Blocks 256 IPs (203.0.113.0 – 203.0.113.255) |
| 2001:db8::1 | Blocks a single IPv6 address |
| 2001:db8::/32 | Blocks an entire IPv6 /32 range |

> Warning: CIDR blocks are broad. Blocking a /16 or larger range can inadvertently block legitimate senders. Start with specific IPs and escalate only when justified.

What Happens to Blocked Mail

| Stage | Outcome |
|---|---|
| SMTP connection | The message is rejected with a policy error (e.g., 554 5.7.1 rejected) |
| Mailbox | The message is not stored |
| Undelivered Emails | The rejection may be logged, but the message is not added to Undelivered Emails (that list is for delivery failures to recipients, not inbound blocks) |
| Sender | The sender may receive a bounce or policy rejection, depending on their server |
| Logs | The rejection is recorded in /var/log/maillog |

> Note: Blocking at SMTP saves server resources compared to content filtering — no message body is scanned, no mailbox storage is consumed.

Verifying a Block

Check that the IP is blocked

```bash

From the server, attempt an SMTP connection from the blocked IP

(run from a machine with that IP, or use a test tool)