Network Configuration Generator
This tool generates ready-to-paste interface configuration snippets for the three most common network operating systems: Cisco IOS/IOS-XE, Juniper Junos, and Fortinet FortiOS. Enter a subnet in CIDR notation, specify an interface name, and get vendor-specific config blocks with IP addressing, descriptions, and access lists.
The generated configurations follow each vendor's best practices for interface setup. Cisco output uses the familiar CLI syntax with subnet masks, Junos uses set-style commands with prefix lengths, and FortiOS uses the GUI-oriented configuration format with wildcard masks for address objects.
Supported Vendors
| Vendor | OS | Config Style |
|---|---|---|
| Cisco | IOS / IOS-XE | CLI commands with dotted-decimal masks |
| Juniper | Junos | Set-style commands with CIDR prefix lengths |
| Fortinet | FortiOS | Object-based config with wildcard masks |
How to Use
- Enter a CIDR block (e.g.,
10.0.1.0/24) for the interface IP addressing. - Specify the interface name using your vendor's naming convention (e.g.,
GigabitEthernet0/1,ge-0/0/0,port1). - Optionally add a description for the interface.
- Copy the generated config for your vendor and paste it into your terminal or configuration management system.
Frequently Asked Questions
What interface naming conventions should I use?
Cisco uses names like GigabitEthernet0/0/0, FastEthernet0/1, or Loopback0. Juniper uses ge-0/0/0, xe-0/0/0, or et-0/0/0 for physical interfaces and lo0 for loopback. FortiOS uses port1, port2, or wan1/wan2 for physical ports and custom names for VLAN interfaces. The generator works with any interface name you provide.
Does the generated config include access lists?
Yes. The Cisco config includes a standard ACL permitting the subnet. Junos includes a firewall filter with a term to accept traffic from the subnet. FortiOS creates an address object for the subnet that can be referenced in firewall policies. These are starting templates — you should review and adjust them for your security requirements.
Can I use this for VLAN interface configuration?
Yes. For Cisco, use an interface name like Vlan100. For Junos, use irb.100 or vlan.100. For FortiOS, you would typically create a VLAN interface under the physical port in the FortiGate GUI, then apply the addressing from the generated config.
What is the difference between Cisco IOS and IOS-XE config syntax?
For basic interface configuration, the syntax is identical between IOS and IOS-XE. Differences appear in advanced features like programmability (RESTCONF/NETCONF on IOS-XE), container-based services, and some platform-specific commands. The interface config generated here works on both platforms.
Is there an API for generating configs programmatically?
Yes. The NetTools REST API provides a /api/config endpoint that accepts CIDR, interface name, vendor, and description parameters and returns configuration snippets as JSON. See the API Documentation page for curl examples and response format.