Vmware Nsx

VMware NSX

> Disclaimer: This is a community-maintained open-source project and is not affiliated with, endorsed by, or sponsored by VMware, Inc. or Broadcom Inc. "VMware" and "NSX" are trademarks of Broadcom. Source code is publicly auditable at github.com/zw008/VMware-NSX under the MIT license.

VMware NSX networking management — 31 MCP tools for segments, gateways, NAT, routing, and IPAM.

> Domain-focused networking skill for NSX-T / NSX 4.x Policy API. > Companion skills: vmware-nsx-security (DFW/firewall), vmware-aiops (VM lifecycle), vmware-monitor (read-only monitoring), vmware-storage (iSCSI/vSAN), vmware-vks (Tanzu Kubernetes), vmware-aria (metrics/alerts/capacity), vmware-avi (AVI/ALB/AKO), vmware-harden (compliance baselines). > | vmware-pilot (workflow orchestration) | vmware-policy (audit/policy)

What This Skill Does

| Category | Tools | Count | |----------|-------|:-----:| | Segments | list, get details, create, update, delete, list ports | 6 | | Tier-0 Gateways | list, get details, BGP neighbors, route table | 4 | | Tier-1 Gateways | list, get details, create, update, delete, route table | 6 | | NAT | list rules, get rule details, create rule, update rule, delete rule | 5 | | Static Routes | list, create, delete | 3 | | IP Pools | list, get allocations, create pool, create subnet | 4 | | Health & Troubleshooting | NSX alarms, transport node status, edge cluster status, manager cluster status, logical port status, VM-to-segment lookup | 6 |

Total: 31 tools (18 read-only + 13 write)

Quick Install

uv tool install vmware-nsx-mgmt
vmware-nsx doctor

When to Use This Skill

Use companion skills for:

Related Skills — Skill Routing

| User Intent | Recommended Skill | |-------------|-------------------| | NSX networking: segments, gateways, NAT, routing, IPAM | vmware-nsx ← this skill | | NSX security: DFW rules, security groups, IDS/IPS | vmware-nsx-security | | Read-only vSphere monitoring, alarms, events | vmware-monitor | | VM lifecycle, deployment, guest ops | vmware-aiops | | Storage: iSCSI, vSAN, datastores | vmware-storage | | Tanzu Kubernetes (vSphere 8.x+) | vmware-vks | | Aria Ops: metrics, alerts, capacity planning | vmware-aria | | Multi-step workflows with approval | vmware-pilot | | Compliance baselines (CIS / 等保 / PCI-DSS), drift detection, LLM remediation advisor | vmware-harden (uv tool install vmware-harden) | | Load balancer, AVI, ALB, AKO, Ingress | vmware-avi (uv tool install vmware-avi) | | Audit log query | vmware-policy (vmware-audit CLI) |

Common Workflows

Create an App Network (Segment + T1 Gateway + NAT)

Pre-flight (judgment, not blind sequence):

Steps: 1. vmware-nsx gateway create-t1 app-t1 --edge-cluster --tier0 --dry-run → review, then run for real 2. vmware-nsx segment create app-web-seg --gateway app-t1 --subnet --transport-zone tz-overlay 3. vmware-nsx nat create app-t1 --action SNAT --source --translated 4. Verify end-to-end: segment list, nat list app-t1, AND test with a VM attached to the new segment

Check Network Health

Judgment: don't just enumerate health endpoints — correlate them. The order below maps cause to symptom: if manager is down, transport nodes will look down too (false positive); fix top-down.

1. vmware-nsx health manager-status — if any manager node is DEGRADED or DOWN, stop here and resolve before trusting downstream signals 2. vmware-nsx health transport-nodes — flag nodes whose tunnel state is not UP for ≥ 5 min; transient blips are normal 3. vmware-nsx health edge-clusters — verify SR placement is balanced; one edge holding 80% of SRs is a single point of failure 4. vmware-nsx health alarms — filter to severity ≥ HIGH; lower severities are usually signal noise 5. Cross-check with vmware-monitor for vSphere host events — a host losing connection to vCenter often masquerades as an NSX problem

Troubleshoot VM Connectivity

Judgment: connectivity failures happen at one of three layers. Identify which layer first, then drill — don't probe randomly.

Steps (stop as soon as the failing layer is identified): 1. Layer 1: troubleshoot vm-segment my-vm-01 → if no port, check vSphere vNIC binding first 2. Layer 1: troubleshoot port-status → admin-down or DFW-blocked? If DFW, jump to vmware-nsx-security 3. Layer 2: gateway routes-t1 app-t1 → expected default route present? If not, T1↔T0 link broken 4. Layer 3: gateway bgp-neighbors tier0-gw → all neighbors ESTABLISHED? Flapping → upstream issue 5. Layer 3: nat list app-t1 → SNAT rule covers the source CIDR? Mis-typed CIDR is the most common cause

Multi-Target Operations

All commands accept --target to operate against a specific NSX Manager from your config:

# Default target (first in config.yaml)
vmware-nsx segment list
Specific target
vmware-nsx segment list --target nsx-prod
vmware-nsx health alarms --target nsx-lab

Usage Mode

| Scenario | Recommended | Why | |----------|:-----------:|-----| | Local/small models (Ollama, Qwen) | CLI | ~2K tokens vs ~8K for MCP | | Cloud models (Claude, GPT-4o) | Either | MCP gives structured JSON I/O | | Automated pipelines | MCP | Type-safe parameters, structured output |

MCP Tools (31 — 18 read, 13 write)

All MCP tools accept an optional target parameter to select which NSX Manager to connect to.

| Category | Tool | Type | Description | |----------|------|:----:|-------------| | Segment | list_segments | Read | List all segments with type, subnet, gateway, transport zone | | | get_segment | Read | Get segment details including ports and subnet config | | | create_segment | Write | Create overlay or VLAN segment with subnet and gateway | | | update_segment | Write | Update segment properties (description, tags, DHCP) | | | delete_segment | Write | Delete a segment (checks for connected ports first) | | | list_segment_ports | Read | List logical ports on a segment with status | | Tier-0 GW | list_tier0_gateways | Read | List Tier-0 gateways with HA mode and edge cluster | | | get_tier0_gateway | Read | Get Tier-0 details: interfaces, routing config, BGP | | | get_tier0_bgp_neighbors | Read | List BGP neighbor sessions with state, ASN, routes | | | get_tier0_route_table | Read | Get Tier-0 routing table (connected, static, BGP) | | Tier-1 GW | list_tier1_gateways | Read | List Tier-1 gateways with linked Tier-0 and edge cluster | | | get_tier1_gateway | Read | Get Tier-1 details: interfaces, route advertisement | | | create_tier1_gateway | Write | Create Tier-1 gateway with edge cluster and Tier-0 link | | | update_tier1_gateway | Write | Update Tier-1 properties (route advertisement, tags) | | | delete_tier1_gateway | Write | Delete a Tier-1 gateway (checks for connected segments) | | | get_tier1_route_table | Read | Get Tier-1 routing table | | NAT | list_nat_rules | Read | List NAT rules on a Tier-1 gateway | | | get_nat_rule | Read | Get NAT rule details (action, source, destination, translated) | | | create_nat_rule | Write | Create SNAT/DNAT/reflexive NAT rule on a gateway | | | update_nat_rule | Write | Update NAT rule properties | | | delete_nat_rule | Write | Delete a NAT rule | | Static Routes | list_static_routes | Read | List static routes on a Tier-0 or Tier-1 gateway | | | create_static_route | Write | Add a static route with network and next-hop | | | delete_static_route | Write | Remove a static route | | IP Pools | list_ip_pools | Read | List IP pools with usage statistics | | | get_ip_pool_allocations | Read | Show allocated IPs from a pool | | | create_ip_pool | Write | Create a new IP address pool | | | create_ip_pool_subnet | Write | Add a subnet/range to an IP pool | | Health | get_nsx_alarms | Read | List active NSX alarms with severity and entity | | | get_transport_node_status | Read | Transport node connectivity and config status | | | get_edge_cluster_status | Read | Edge cluster member status and failover config | | | get_manager_cluster_status | Read | NSX Manager cluster health and node roles | | Troubleshoot | get_logical_port_status | Read | Logical port admin/operational status and link state | | | find_vm_segment | Read | Find which segment(s) a VM is connected to by name |

Read/write split: 18 tools are read-only, 13 modify state. Write tools require explicit parameters and are audit-logged. All write operations support dry-run mode.

CLI Quick Reference

# Segments
vmware-nsx segment list [--target ]
vmware-nsx segment get 
vmware-nsx segment create  --gateway  --subnet  --transport-zone  [--dry-run]
vmware-nsx segment update  --description "new desc" [--dry-run]
vmware-nsx segment delete  [--dry-run]
vmware-nsx segment ports 
Tier-0 Gateways
vmware-nsx gateway list-t0
vmware-nsx gateway get-t0 
vmware-nsx gateway bgp-neighbors 
vmware-nsx gateway routes-t0 
Tier-1 Gateways
vmware-nsx gateway list-t1
vmware-nsx gateway get-t1 
vmware-nsx gateway create-t1  --edge-cluster  --tier0  [--dry-run]
vmware-nsx gateway update-t1  --route-advertisement connected,nat [--dry-run]
vmware-nsx gateway delete-t1  [--dry-run]
vmware-nsx gateway routes-t1 
NAT
vmware-nsx nat list 
vmware-nsx nat get  
vmware-nsx nat create  --action SNAT --source  --translated  [--dry-run]
vmware-nsx nat update   --translated  [--dry-run]
vmware-nsx nat delete   [--dry-run]
Static Routes
vmware-nsx route list 
vmware-nsx route create  --network  --next-hop  [--dry-run]
vmware-nsx route delete   [--dry-run]
IP Pools
vmware-nsx ippool list
vmware-nsx ippool allocations 
vmware-nsx ippool create  [--dry-run]
vmware-nsx ippool add-subnet  --start  --end  --cidr  [--dry-run]
Health & Troubleshooting
vmware-nsx health alarms [--severity CRITICAL]
vmware-nsx health transport-nodes
vmware-nsx health edge-clusters
vmware-nsx health manager-status
vmware-nsx troubleshoot port-status 
vmware-nsx troubleshoot vm-segment 
Diagnostics
vmware-nsx doctor [--skip-auth]

> Full CLI reference with all options and output formats: see references/cli-reference.md

Troubleshooting

"Segment not found" when querying

Segment display names and Policy API IDs can differ. Use vmware-nsx segment list to get the exact ID. The Policy API uses the segment id field, not display_name. Common mistakes: using the display name with spaces instead of the hyphenated ID.

NAT rule creation fails with "gateway not found"

NAT rules are created on Tier-1 gateways (or Tier-0 for some topologies). Verify the gateway name with vmware-nsx gateway list-t1. The gateway must have an edge cluster assigned for NAT to function.

BGP neighbor shows "Connect" or "Active" state

The BGP session is not established. Common causes: 1. Peer IP unreachable from the edge node — check physical uplinks and VLAN config 2. ASN mismatch — compare local and remote ASN in bgp-neighbors output 3. Firewall blocking TCP 179 — check edge node firewall rules (not NSX DFW) 4. MD5 password mismatch — verify authentication settings on both sides

Transport node status "degraded"

A transport node in degraded state has partial connectivity. Steps: 1. Check vmware-nsx health transport-nodes for the specific failure reason 2. Common cause: tunnel endpoint (TEP) unreachable — verify underlay MTU (minimum 1600 for Geneve) 3. Check NTP sync between NSX Manager and transport nodes 4. If recently upgraded, verify the host switch config matches NSX Manager expectations

"Password not found" error

The password environment variable is missing. Variable names follow the pattern VMWARE__PASSWORD where hyphens become underscores. Example: target nsx-prod needs VMWARE_NSX_PROD_PASSWORD. Check your ~/.vmware-nsx/.env file.

Safety

Setup

uv tool install vmware-nsx-mgmt
mkdir -p ~/.vmware-nsx
cp config.example.yaml ~/.vmware-nsx/config.yaml
Edit config.yaml with your NSX Manager targets
Add to ~/.vmware-nsx/.env (create if missing, chmod 600):
VMWARE_NSX_PROD_PASSWORD=
chmod 600 ~/.vmware-nsx/.env
vmware-nsx doctor

> All tools are automatically audited via vmware-policy. Audit logs: vmware-audit log --last 20

> Full setup guide with multi-target config, MCP server setup, and Docker: see references/setup-guide.md

Architecture

User (natural language)
  |
AI Agent (Claude Code / Goose / Cursor)
  | reads SKILL.md
vmware-nsx CLI or MCP server (stdio transport)
  | NSX Policy API (REST/JSON over HTTPS)
NSX Manager
  |
Segments / Gateways / NAT / Routes / IP Pools / Transport Nodes

The MCP server uses stdio transport (local only, no network listener). Connections to NSX Manager use HTTPS on port 443.

Audit & Safety

All operations are automatically audited via vmware-policy (@vmware_tool decorator):

vmware-policy is automatically installed as a dependency — no manual setup needed.

License

MIT — github.com/zw008/VMware-NSX