Member Avatar for azharalibuttar

It’s a bit older but a very cheap way to use a Linux Machine as an internet Router/Gateway. There is no need to be a LINUX expert to do this task. No need to have two physical fast Ethernet cards. Sharing internet connection with only one physical fast Ethernet card is very easy.

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This thread explores three common choices for providing gateway services: a DIY Linux gateway, a consumer hardware router, or a dedicated UTM appliance. describes a one-NIC Linux approach (works for small home setups), points out the ease of using a hardware router, correctly highlights the safety of separate NICs, and recommends UTM appliances for larger networks. Below are practical, modern tips and a minimal example to bridge the gap between "it works" and "it works reliably and safely."

Checklist and quick steps to get a stable Linux gateway

  • Decide topology: single-NIC NAT (virtual interfaces/bridge) for tiny home labs; two physical NICs (WAN + LAN) for production or any public-facing services.
  • Enable IPv4 forwarding and create NAT. Use nftables on modern systems; keep a fallback to iptables only if required.
  • Provide DHCP/DNS locally (dnsmasq or isc-dhcp-server) and minimize services on the gateway.
  • Harden kernel networking (rp_filter, ICMP rate limits, disable source routing) and use logging/limits for connection tracking to avoid overload.
  • Test from a client, confirm outbound and hairpin (NAT loopback) behavior, and monitor CPU/conntrack counts.

Minimal commands (examples — adapt interface names)

# enable IPv4 forwarding (temporary)
sysctl -w net.ipv4.ip_forward=1

# simple NAT with nftables (modern)
nft add table ip nat
nft 'add chain ip nat postrouting { type nat hook postrouting priority 100 ; }'
nft add rule ip nat postrouting oif "eth0" masquerade

Recommendations
For a few devices a single-NIC setup can be fine, but two NICs or a dedicated appliance is safer for reliability and security. For an out-of-the-box firewall/router consider hardened projects like pfSense or OPNsense; for kernel-level filtering and NAT use the Netfilter/nftables documentation (see Netfilter and pfSense).

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Member Avatar for lordspace

Another option is to use a hardware router (which enables wireless network as well) e.g. D-Link

Member Avatar for icyshout

its better to use two physically seperate NIC's

Member Avatar for Dima Bilan

There are some all-in-one UTMs that allow you to control your in-and-out traffic very efficiently like ideco gateway
You can set all kinds of restrictions rules per user, per group and more , its also a firewall and mail server etc , however it requires a dedicated server
so yeah this is what i chose for my network of 100 worksattions and i can recommend it too, price is competative comaredto alternatives with such functionality

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