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Verify commands against the exact hardware and software release before applying them.
Example: GigabitEthernet1/0/48. New lines and CLI metacharacters are rejected.
Use a documentation-style peer or endpoint label that follows your naming standard.
Changing mode keeps the other examples available but generates only commands relevant to the selected path.
For disruptive changes, consider keeping the interface shut until the stanza and peer are ready.
Treat every generated stanza as a draft until it has been compared with the target and peer configurations.
Adds configure terminal/end, or configure/commit for IOS XR. Off is neutral.
{{ include_wrappers ? 'Enabled' : 'Disabled' }}
Blank is neutral and omits the command.
bytes
Blank is neutral; verify interface and transceiver support before forcing speed.
Blank is neutral; half duplex is retained only for interfaces that explicitly support it.
Blank is neutral. Example: 2001:db8:44::2/64.
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StepCommandAreaPurposeOperator reviewCopy
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LevelCheckDetailRecommendationCopy
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Cisco ACL Generator Generate Cisco ACL commands from IPv4 flow rows for IOS, NX-OS, and ASA with platform-aware address conversion and safety checks before use.
VLAN Config Consistency Checker Compare switch VLAN evidence with intended trunk and native rules plus database, reserved-VLAN, and VLAN 1 policy before a change.
Static Route Commands Generator Generate reviewed static-route commands across host and network CLIs with CIDR normalization plus priority checks and rollback-ready delete output.
BGP Prefix List Generator Turn IPv4 and IPv6 CIDR rows into platform-specific prefix-list syntax, with normalized networks and ordered-policy warnings.

An interface stanza is short enough to paste in seconds and important enough to disconnect a site. Its correct shape depends first on the port’s role: a routed interface carries IP traffic directly, an access switchport places an endpoint in one data VLAN, and a trunk carries tagged traffic for several VLANs between network devices.

Those roles solve different problems. A routed link needs an address and a contiguous subnet mask. An access port needs the intended data VLAN and may also need a voice VLAN or edge protections. A trunk needs agreement with its peer about trunking, the native VLAN, and which VLANs are allowed. A command can be valid on its own while still being wrong for the peer, the existing configuration, or the change plan.

Interface role Primary decisions Consequential mismatch
Routed Layer 3 IPv4 address, mask or prefix, optional IPv6 address Wrong subnet, duplicate address, or missing subinterface encapsulation
Access switchport Data VLAN, optional voice VLAN, edge protections Endpoint placed in the wrong broadcast domain or disabled by protection policy
Trunk switchport Native VLAN, allowed VLAN policy, negotiation behavior Native-VLAN mismatch, missing traffic, or unintended VLAN carriage

Platform family changes the command vocabulary and the configuration session. IOS and IOS XE commonly cover routed, access, and trunk ports. Older IOS platforms may require an explicit 802.1Q encapsulation command. NX-OS has its own reserved-VLAN considerations, while the supported IOS XR path is routed-only and uses a commit workflow.

Administrative state is part of the risk decision, not just a final line. Applying no shutdown may allow traffic immediately; leaving the interface shut gives the operator time to review the complete stanza and peer before activation. Forced MTU, speed, or duplex settings can also create failures when hardware or the far end does not match.

Generated syntax cannot replace a pre-change capture, peer review, rollback plan, or model-and-release check. It does not inspect the live device, merge the current interface stanza, create VLANs, detect duplicate addresses, or prove that an optional command is supported.

How to Use This Tool:

Start from the target operating system and interface role, then enter only the values that belong to that branch.

  1. Choose the Syntax profile and enter one Interface name. Use the IOS XR profile only for a routed interface.
  2. Choose Routed, Access, or Trunk. For routed mode, supply IPv4 and a mask or prefix; for access mode, confirm the data and optional voice VLANs; for trunk mode, choose the native VLAN and the allowed-VLAN operation.
  3. Set the Administrative state. Keep a disruptive or incomplete change shut until the stanza, peer, and rollback have been reviewed.
  4. Add only supported advanced lines such as MTU, speed, duplex, IPv6, edge spanning-tree behavior, BPDU Guard, storm control, native-VLAN tagging, or DTP suppression.
  5. Read every row in Validation review, then compare the complete interface configuration with the current device and peer. Resolve warnings before applying any command.

Interpreting Results:

A ready configuration means the entered values passed the generator’s syntax and range checks. It does not mean the change is safe for the live network.

  • Compare the command plan with the current interface stanza so a replacement or mode change does not erase required settings.
  • Verify the peer’s mode, native VLAN, allowed VLANs, addressing, speed, duplex, and MTU where applicable.
  • Treat every warning as an operator check. The warning count is not a risk score, and zero warnings is not approval to deploy.

Technical Details:

Cisco interface syntax is assembled as an ordered stanza: optional session entry, interface context, optional description, role-specific commands, optional tuning, administrative state, and optional session exit or commit. The selected profile changes command wording and valid mode combinations.

Rule Core

Profile Supported path Profile-specific rule
IOS / IOS XE Routed, access, trunk Optional wrappers use configure terminal and end.
IOS legacy dot1q Routed, access, trunk A trunk adds switchport trunk encapsulation dot1q.
NX-OS Routed, access, trunk Edge behavior uses spanning-tree port type edge; IOS nonegotiate is not emitted.
IOS XR Routed only IPv4 uses ipv4 address; optional wrappers use configure and commit.

Role-specific commands follow a fixed decision order:

  1. Routed: a physical non-subinterface on IOS-style profiles receives no switchport, followed by IPv4 and optional IPv6 addressing. Virtual interfaces and dotted subinterfaces do not receive the automatic no switchport line.
  2. Access: the stanza sets switchport, static access mode, and an access VLAN. Voice VLAN, edge spanning-tree behavior, BPDU Guard, and broadcast storm control are conditional additions.
  3. Trunk: the stanza sets switchport, static trunk mode, native VLAN, and an allowed-VLAN policy. Native tagging and DTP suppression are conditional and profile-dependent.

Transformation Core

IPv4 prefixes from 0 through 32 are converted to contiguous dotted masks. A dotted mask is accepted only when its one-bits are contiguous. For example, /30 normalizes to 255.255.255.252. IPv6 is optional in routed mode and must use address/prefix notation with a prefix from 0 through 128.

VLAN IDs are limited to 1 through 4094. A trunk list accepts comma-separated IDs and ascending ranges, removes duplicates, sorts the result, and compresses adjacent values. Thus 30,10,31-40,20,999 becomes 10,20,30-40,999. The operation then determines whether that normalized list replaces, adds to, or removes from the existing allowed list; all and none are emitted directly.

Value Accepted boundary Important interpretation
Access or native VLAN 1 to 4094 inclusive Existence and policy are not checked.
Voice VLAN 1 to 4094; 0 omits the command Endpoint discovery and voice policy remain external checks.
MTU 576 to 9216 inclusive, or blank Hardware and end-to-end support are not inferred.
Storm-control level 0 to 100 percent inclusive, or blank The emitted value uses two decimal places; confirm platform syntax and action.

The NX-OS review flags VLANs 3968 through 4047 and VLAN 4094 because they may be reserved for internal use on relevant Nexus platforms. It also flags a replacement trunk list that omits the native VLAN, native VLAN 1, broad all or none policies, and routed subinterfaces whose required 802.1Q encapsulation cannot be inferred.

Limitations and Safety Notes:

The configuration is generated entirely from entered values. There is no connection to a switch or router, no running-configuration lookup, and no knowledge of chassis, module, transceiver, software release, IP address management, routing plan, or peer state.

  • Capture the current interface and related VLAN or routing configuration before making a change.
  • Review the exact command reference for the target model and release, especially for advanced and NX-OS features.
  • Prepare a tested rollback and an out-of-band recovery path for changes that can cut management or production traffic.

Worked Examples:

IOS trunk with a replacement list

Selecting IOS / IOS XE, trunk mode, native VLAN 999, and 10,20,30-40,999 produces a static trunk stanza with seven commands when a description is present and wrappers are off. The review confirms 14 unique allowed VLAN IDs and still warns that the current configuration was not inspected.

IOS XR routed handoff

An IOS XR routed interface using 192.0.2.2 and prefix 30 normalizes the mask to 255.255.255.252. With wrappers enabled, the draft begins with configure, uses ipv4 address, and ends with commit. The documentation address is safe for an example but must be replaced with the assigned production address.

References: