NWDiag

NWDiag draws network diagrams as horizontal bands, one per network, with nodes attached to each. A node on two networks appears on both bands automatically.

That single behaviour is why it beats hand-drawing for anything with more than two subnets.

#What it is good at

• Subnet and VLAN documentation with addresses.

• Small to medium network topologies that change.

• Documentation generated from an IP allocation table.

#What it draws

#A worked example

Three networks with a host on two of them:

The source, which you can paste into a new diagram and edit:

nwdiag {
  network dmz {
    address = "10.0.1.0/24";
    description = "Public";
    lb01 [address = "10.0.1.10"];
    web01 [address = "10.0.1.11"];
  }
  network app {
    address = "10.0.2.0/24";
    description = "Application";
    web01 [address = "10.0.2.11"];
    api01 [address = "10.0.2.21"];
  }
  network data {
    address = "10.0.3.0/24";
    description = "Data";
    api01 [address = "10.0.3.21"];
    db01 [address = "10.0.3.31"];
  }
}

#A few things that catch people out

• Repeat the node name in each network it belongs to; NWDiag joins them for you.

• Addresses are free text, so a typo renders happily. Check them against your allocation table.

• Above roughly thirty nodes it gets tall. Split by site or tier.

#Related

Thirty-one languages. Nobody knows them all.