Mini Relay Server is a free portable SMTP server that runs locally on your computer and acts as your own personal mail relay. Once launched, it listens on localhost and allows you to send outgoing email directly to recipient mail servers without relying on your Internet Service Provider SMTP server.
This lightweight tool is especially useful for users who frequently move between different networks where SMTP restrictions, blocked ports, or authentication issues can prevent normal email sending. By routing email through localhost, it provides a consistent and independent way to send mail from almost any connection.
Mini Relay | Portable SMTP Server
Simply configure your email client to use IP address 127.0.0.1 as the outgoing SMTP server, and the portable smtp server will relay and handle message delivery in the background.
Mini Relay Server operates as a small, standalone SMTP relay that forwards messages directly to recipient mail servers using standard SMTP delivery. Because it runs locally and requires no installation, it can be stored and launched from a USB flash drive on any compatible Windows system.
What Is a Portable SMTP Relay Server?
A portable SMTP relay server allows you to send email without depending on a specific provider SMTP gateway. Instead of authenticating through an ISP mail server, messages are delivered directly using DNS mail exchange records.
This approach is useful when:
- Your ISP blocks outgoing SMTP ports.
- You are connected to public or corporate networks with mail restrictions.
- You switch networks frequently and want consistent mail sending.
- You need a lightweight mail relay for testing or development.
Key Features
- Fully Portable: Runs without installation and leaves no system footprint.
- Local SMTP Server: Uses localhost 127.0.0.1 as the outgoing mail server.
- ISP Independent: Bypasses ISP SMTP servers entirely.
- Minimal Configuration: Requires only basic SMTP client settings.
- Lightweight: Extremely small file size and low resource usage.
- Background Operation: Runs quietly while your email client sends messages.
Who Should Use Mini Relay?
It is well suited for users who need a simple and portable solution for sending email across varying network environments.
Typical use cases include:
- Travelers who frequently connect to hotel, airport, or public WiFi networks.
- System administrators testing mail delivery.
- Developers who need a local SMTP relay for applications.
- Users whose ISPs impose strict SMTP limitations.
How to Use Mini Relay Server
Getting started is straightforward:
- Download and extract Mini Relay Server to your USB drive or local folder.
- Launch the executable.
- Configure your email client to use 127.0.0.1 as the SMTP server.
- Send email normally through your email client.
Once running, MiniRelay will automatically relay outgoing messages to recipient mail servers without additional authentication.
Specifications | Project Page | Download Link
- Author's Website: Project Page
- Developer: NetVicious
- License: Freeware
- Supported Operating System: Windows
- Extracted File Size: 296 KB
- Editor's Rating: 4 Star
- Download: Mini Relay Download
Final Thoughts
Mini Relay Server is a simple yet powerful portable SMTP solution for users who need independence from ISP mail servers. Its tiny footprint, ease of use, and portability make it a valuable utility for mobile professionals, developers, and anyone who regularly encounters email sending restrictions.
If you are looking for a free, lightweight, and portable SMTP relay that works anywhere without installation, this tiny relay server is an excellent tool to keep on your USB flash drive.