D7Demigodseven
Network Workbench

Discover the Network.

DNS resolution, response timing, subnet analysis, address conversion, native test helpers, and dense Cisco, FortiGate, Linux and systems references — all in one compact workbench.

DNS + Response Monitor

Main live tool: DNS resolution plus repeated browser response timing and graph.

DNS: idleWeb probe: idleSamples: 0
Resolved IP-
Latest-
Minimum-
Average-
Maximum-
Jitter-
Browser limitation: webpages cannot send raw ICMP ping packets or true hop-by-hop traceroute. This tool does real DNS resolution via DNS-over-HTTPS and times browser web requests. Use the native command builder below for ICMP ping, traceroute, MTR, PathPing and packet-level tests.

Advanced IPv4 Subnet Analyzer

Network, broadcast, wildcard mask, range, host count, binary and address scope.

Network-
Broadcast-
Usable Range-
Usable Hosts-
Subnet Mask-
Wildcard Mask-
Total Addresses-
Host Bits-
Class-
Scope-
IP Integer-
Reverse Zone-

DNS Record Lookup

A, AAAA, MX, TXT, NS, CNAME and SOA via DNS-over-HTTPS.

Ready.

Address Converter

Native Test Command Builder

Browser / Local View

Common Ports

PortProtocolService
22TCPSSH/SFTP
25TCPSMTP
53TCP/UDPDNS
67/68UDPDHCP
80TCPHTTP
123UDPNTP
161/162UDPSNMP
389TCP/UDPLDAP
443TCPHTTPS
445TCPSMB
514UDPSyslog
636TCPLDAPS
3389TCP/UDPRDP

CIDR + Address Memory

CIDRMaskAddressesUsable
/24255.255.255.0256254
/25255.255.255.128128126
/26255.255.255.1926462
/27255.255.255.2243230
/28255.255.255.2401614
/29255.255.255.24886
/30255.255.255.25242
/31255.255.255.25422
/32255.255.255.25511
RFC1918: 10.0.0.0/8 | 172.16.0.0/12 | 192.168.0.0/16
Link-local: 169.254.0.0/16 | CGNAT: 100.64.0.0/10 | Loopback: 127.0.0.0/8

IPv6 Analyzer

Expand, compress, classify and inspect IPv6 addresses and prefixes.

Compressed-
Expanded-
Prefix-
Host Bits-
Network-
Type-
Solicited Notes-
Address Space128 bits

VLSM Planner

Allocate variable-sized IPv4 subnets from largest requirement to smallest.

ACL / Wildcard Builder

Build common Cisco-style wildcard matching patterns.

CIDR Overlap Detector

Check whether two IPv4 networks intersect.

Route Summarization Helper

Find the smallest IPv4 supernet covering a list of addresses or networks.

HTTP Timing Inspector

Measure repeated browser request timing to an HTTPS target.

Cross-origin browser requests can be opaque. This tool measures elapsed request time but cannot reliably read remote status codes, headers, server timing, or certificate data unless that server explicitly permits CORS.

TLS / Certificate Inspector Helper

Generate native commands for certificate, protocol and cipher inspection.

Browsers intentionally do not expose arbitrary remote TLS certificate chains to page JavaScript. Use these native commands for the real certificate, protocol and cipher details.

TCP Flags

Quick packet interpretation.

SYNStart / synchronize a TCP connection.
ACKAcknowledges received sequence data.
FINGraceful close.
RSTImmediate reset or refusal.
PSHDeliver buffered data promptly.
URGUrgent pointer is significant.

ICMP Memory

Useful IPv4 diagnostic types.

Echo Request / ReplyClassic ping behavior.
Destination UnreachableNetwork, host, protocol or port cannot be reached.
Time ExceededTTL expired; foundational to traceroute.
Fragmentation NeededImportant for Path MTU Discovery.

IPv6 Memory

High-value IPv6 ranges.

::1/128Loopback.
fe80::/10Link-local.
fc00::/7Unique local addresses.
ff00::/8Multicast.
2000::/3Global unicast space.
2001:db8::/32Documentation examples.

Linux Network Commands

Linux Navigation + System

Cisco IOS - Show / Troubleshoot

Cisco IOS - Configure

FortiGate - Inspect / Diagnose

FortiGate - Configure

OSI / TCP-IP Stack

What lives where, and what to check first.

7ApplicationHTTP, HTTPS, DNS, SSH, SMTP, SNMP
6PresentationEncoding, compression, TLS concepts
5SessionSession establishment and control
4TransportTCP, UDP, ports, retransmits, state
3NetworkIPv4/IPv6, routing, ICMP, TTL
2Data LinkEthernet, MAC, ARP, VLAN, STP
1PhysicalCable, optics, radio, signal, duplex
TCP/IP shorthand: Application → Transport → Internet → Link.

Troubleshooting Ladder

Work from the local edge outward.

01PhysicalLink up? Power? Cable? Wi-Fi association? Duplex/speed?
02AddressingCorrect IP, mask/prefix, VLAN and default gateway?
03Local L2ARP/neighbor entry? MAC learned? Correct switchport/VLAN?
04RoutingDoes a route exist? Is the next hop reachable? Is return routing valid?
05Name ResolutionDoes DNS resolve? Correct record? Correct resolver?
06Policy / NATFirewall rule, ACL, NAT, security profile, asymmetric path?
07ServiceIs the application listening on the expected port/interface?
08CapturePacket capture both directions; compare working vs failing host.

TCP State Memory

Connection lifecycle essentials.

SYNClient asks to start a TCP session.
SYN-ACKServer acknowledges and agrees.
ACKThree-way handshake completes.
FINGraceful close request.
RSTImmediate reset/rejection.
TIME_WAITSocket waits before tuple reuse.

DHCP DORA

Client address acquisition.

DiscoverClient broadcasts for DHCP servers.
OfferServer proposes an address and options.
RequestClient requests the chosen offer.
AcknowledgeServer confirms the lease.

DNS Resolution Path

Where name resolution can fail.

Local cacheBrowser / OS may already know the answer.
Recursive resolverYour configured DNS server takes the query.
Root / TLDDelegation points toward authoritative DNS.
AuthoritativeFinal record source for the zone.

MTU / MSS

Classic hidden connectivity problem.

Ethernet MTUTypically 1500 bytes.
IPv4 TCP MSSOften 1460 with MTU 1500.
IPv6 TCP MSSOften 1440 with MTU 1500.
SymptomSmall traffic works, larger transfers stall.

Routing Truths

Useful mental shortcuts.

Longest prefix wins/28 beats /24 beats /0.
Return path mattersForward success alone is not enough.
Next hop must resolveRouting still depends on local L2 reachability.
Default route0.0.0.0/0 catches what nothing more specific matches.

Remember This

High-value troubleshooting reminders.

DNS success ≠ service successName resolution only proves DNS.
Ping failure ≠ host downICMP may be filtered.
Network ≠ gatewayThe gateway is a host address inside the subnet.
Document changesEspecially before and after production work.

Python Networking

Useful standard-library snippets for DNS, sockets, HTTP and IP math.

Python System / Automation

Files, subprocesses, JSON, environment and lightweight scripting.

AWS Identity / Config

Know who you are, where you are, and which profile is active.

AWS Compute / Network

EC2, VPC, subnets, security groups and route tables.

AWS Storage / Logs

S3, CloudWatch and common operational checks.

Oracle OCI Identity / Config

CLI setup, compartments, regions and tenancy context.

Oracle OCI Compute

Instances, VNICs, shapes and lifecycle operations.

Oracle OCI Networking

VCNs, subnets, route tables, security lists and gateways.

Azure Identity / Subscription

Login, current account, subscriptions and defaults.

Azure Compute

Virtual machines, resource groups and power state.

Azure Network

VNets, NICs, NSGs, IPs and route tables.

Google Cloud Identity / Config

Accounts, project, region, zone and active context.

Google Compute Engine

Instances, machine state and SSH.

Google Cloud Network

VPCs, subnets, firewall rules, routes and addresses.

Docker

Containers, images, logs, networks and shell access.

Kubernetes

Contexts, pods, services, logs, exec and rollout checks.

Terraform

Initialize, validate, plan, apply, state and outputs.