Common ports and services
Well-known services that come up often during firewall review, ACL work, and flow verification.
Searchable
| Port | Protocol | Service | Notes |
|---|
Reference
Searchable quick references for common ports, subnet masks, commands, and frequently used IPv4/IPv6 ranges.
IPv4 prefix reference
Fast lookup for masks, wildcard masks, address counts, and usable host counts.
/0 to /32
| Prefix | Mask | Wildcard | Total | Usable |
|---|
Command library
Quick operational commands grouped across common platforms for show, trace, and lookup workflows.
CLI snippets
Private, reserved, and documentation ranges
Ranges you repeatedly need for design review, filtering decisions, and sanity checks.
IPv4 + IPv6
Documentation networks like
192.0.2.0/24, 198.51.100.0/24, and 203.0.113.0/24
are ideal for examples and runbooks because they are not routed on the public Internet.
Planning
Design and pre-change helpers for subnetting, summarization, allocation, and interface config generation.
IPv4 subnet calculator
Enter an IPv4 address plus prefix or mask to compute the full network boundary and host range.
Calculator
Results update locally in your browser.
Route summarizer
Paste newline-separated CIDRs and collapse them into the smallest exact covering set.
Summarization
VLSM planner
Allocate largest-first subnets from a parent CIDR. Use one requirement per line: Name, hosts.
Address plan
| Name | Need | Allocated | Mask | Usable | Host range |
|---|
Interface config generator
Generate a starting interface template for Cisco IOS, Cisco NX-OS, or Junos.
Template
Troubleshooting
Symptom-driven checklists to reduce missed layers and speed up structured triage.
Symptom-based troubleshooting assistant
Pick a symptom to get likely causes, first checks, command ideas, and verification targets.
Runbook
Suggested command focus
Fast triage workflow
A condensed path that keeps first response disciplined before diving into protocol-level detail.
Checklist
1. Establish blast radius
- Single host, single VLAN, single site, or network-wide?
- When did it last work, and what changed immediately before failure?
- Can you reproduce the issue consistently or only under load / time window?
2. Confirm the forwarding path
- Source addressing, default gateway, ARP / ND resolution, VLAN membership.
- Interface state, errors, speed / duplex, optics, STP state, PoE if relevant.
- Routing decision, next hop resolution, ACL / firewall policy, NAT, return path.
3. Verify after the fix
- Confirm counters stop increasing and routes / neighbors stabilize.
- Re-test from both directions where asymmetric paths are possible.
- Capture the exact root cause and permanent control to prevent recurrence.
The browser can help you think and calculate, but it cannot directly run ping, traceroute, SSH, SNMP, NetFlow,
packet capture, or vendor APIs without an external backend. Use this section as the decision support layer.
Verification
Validate inputs, normalize values, and compare expected vs. actual config or inventory lines.
Value validator and normalizer
Paste one value and check whether it matches common network objects such as IPs, MACs, VLAN IDs, ASNs, and hostnames.
Sanity check
Expected vs. actual line compare
Compare two lists of lines to spot missing and extra statements regardless of order.
Diff