Importing Running-Configs

Closing the Lab Workflow Loop

In standard network engineering workflows:

1. You design the addressing plan in NetCalc Pro.
2. You generate Cisco IOS commands and paste them into your devices or Cisco Packet Tracer.
3. You make adjustments directly on the CLI during hands-on troubleshooting (adding interfaces, adjusting static routes, tweaking NAT or ACLs).
4. Connectivity issues arise: “ping fails”, but Packet Tracer does not explain why.

To avoid tedious manual re-entry of changes made in the simulator, NetCalc Pro includes the RunningConfigParser module. This component parses raw text from a show running-config command and reconstructs a complete device model directly inside your project.

Once imported, the device can immediately be inspected by NetCalc Pro’s Network Linter to identify the root cause of connectivity failures.

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How to Import a Configuration

1. In your router or switch CLI (in Packet Tracer or physical terminal), execute:

   enable
   show running-config

2. Select and copy the entire output text (including comments, exclamation marks !, and interface blocks).
3. In NetCalc Pro, select your project in the sidebar.
4. Click Import Running-Config (or choose it from the project’s action menu).
5. Paste the text into the import sheet and confirm.
6. The app automatically creates a new CiscoDevice populated with the extracted hostname, interfaces, routing tables, and security settings.

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Parser Architecture: Fault Tolerance & Transparency

Real-world production or lab configurations often contain hundreds of lines irrelevant to layer 2/3 topology planning (e.g., spanning-tree mode pvst, crypto pki trustpoint, line con 0 details, logging parameters).

NetCalc Pro’s parser is designed around two engineering principles:

1. Graceful Fault Tolerance

The parser never throws a fatal error when encountering unfamiliar commands or hardware-specific syntax. Blocks are recognized by standard contextual keywords (interface, router ospf, ip dhcp pool, vlan) and terminated cleanly by standard delimiters (! or exit/end).

2. Complete Transparency (unrecognizedLines)

Unrecognized commands are not discarded silently. They are collected in the unrecognizedLines array and displayed in a dedicated review sheet. You always know exactly which lines became active model objects and which lines were auxiliary commands.

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Recognized Syntax Elements

The parser supports all configuration directives produced by NetCalc Pro’s CLI generator:

Feature	Parsed Commands and Blocks
Device Identity	hostname <name>
Physical & Virtual Interfaces	interface <name>, description <text>, ip address <ip> <mask>, shutdown / no shutdown
Sub-interfaces & Trunking	encapsulation dot1Q <vlan_id>, switchport mode access, switchport mode trunk, switchport access vlan <id>, switchport trunk allowed vlan <list>
VLAN Database	vlan <id>, name <name>
Static Routing	ip route <dest_network> <mask> <next_hop>
OSPF	router ospf <process_id>, network <ip> <wildcard> area <area_id>
RIPv2	router rip, version 2, no auto-summary, network <ip>, passive-interface <name>
EIGRP	router eigrp <as_number>, no auto-summary, network <ip> [wildcard]
DHCP Server	ip dhcp pool <name>, network <ip> <mask>, default-router <ip>, dns-server <ip>, automatically linking preceding ip dhcp excluded-address ranges
NAT / PAT	ip nat inside source list <acl> interface <wan> overload, ip nat inside source static entries, interface tags ip nat inside and ip nat outside
Access Control Lists	access-list <id> permit/deny <protocol> ..., interface directives ip access-group <id> in/out
Device Hardening	enable secret <pass>, service password-encryption, banner motd #<text>#, ip domain-name <domain>

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Instant Pre-Flight Diagnostics

As soon as a device is imported, it participates in project-wide analysis. Clicking Lab Verification instantly highlights whether the imported running-config introduced duplicate IPs, overlapping subnets, or missing OSPF network statements.