dnsmasq DNS Forwarder DHCP and TFTP Server

This is a repackaged open source software product wherein additional charges apply for cloudimg support services.

## Pre hardened dnsmasq by cloudimg - DNS, DHCP and TFTP in one lightweight daemon

dnsmasq is a widely deployed network infrastructure daemon that provides a caching DNS forwarder, a DHCP server, a TFTP and PXE boot server, and IPv6 router advertisement from a single small binary. This cloudimg image delivers dnsmasq fully installed, hardened, and running as a systemd service, so a secure caching name server is answering queries within minutes of launch, eliminating hours of manual package installation, configuration, and security hardening.

## Why choose this image over a manual install?

Installing dnsmasq from a package repository is straightforward, but hardening it against DNS amplification abuse, disabling the operating system stub resolver, running it unprivileged, closing unnecessary ports, and validating the configuration takes real expertise and time. This image completes all of that before first boot:

• Not an open resolver out of the box: the local-service setting means dnsmasq answers only clients whose source address is on a local subnet of the instance, and silently drops every other source, blocking DNS amplification and reflection abuse with no post launch configuration
• No default credentials: dnsmasq has no login or password, so there is nothing to leak or rotate
• The operating system stub resolver is disabled so dnsmasq cleanly owns port 53 on both UDP and TCP
• DHCP and TFTP ship disabled with their ports closed in the security group, ready to enable only when you need them on a network you own
• One small daemon replaces separate BIND, DHCP, and TFTP servers for local name resolution and address assignment

## How it works

dnsmasq is driven entirely by plain text configuration under /etc/dnsmasq.conf and /etc/dnsmasq.d. This image ships a documented drop in at /etc/dnsmasq.d/00-cloudimg.conf that ignores the host resolver list and forwards to explicit upstream resolvers, caches answers locally, refuses to forward unqualified names and private reverse lookups, and serves a demonstration local host record so a DNS round trip works immediately with no upstream dependency. The whole configuration lives in version controllable text and reloads with a single command.

## Secure first boot

On first launch a one shot systemd service resolves the instance address, reasserts the secure configuration, verifies the configuration syntax, starts dnsmasq, and proves both the local record and upstream forwarding are answering, all before recording the endpoint details in a file only the root user can read.

## Deploying on AWS

Launch the image into any VPC subnet and point your clients, your router, or your VPC DHCP options at the instance private IP for immediate DNS forwarding. The security group ships with only port 53 open on UDP and TCP for DNS, plus port 22 for administration; open the DHCP and TFTP ports only when you enable those services. Size the instance to your query volume and DHCP lease count.

## Get started

1. Launch the image in your target VPC subnet

2. Verify DNS forwarding by querying the instance, for example dig @ example.com

3. Review /etc/dnsmasq.d/00-cloudimg.conf to understand the shipped defaults

4. Point your clients or router at the instance for DNS resolution

5. Optionally widen the served client scope to trusted subnets, enable DHCP for your own network, or turn on TFTP and PXE boot, all documented in the paired user guide

## 24/7 expert support from cloudimg

cloudimg engineers provide around the clock assistance with resolver hardening, client scoping, upstream and cache tuning, DHCP scope design, TFTP and PXE boot configuration, IPv6 router advertisement, monitoring, and dnsmasq version upgrades, by email and live chat.

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