Automation Controls Toolbox
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Networking

Industrial networking helpers for plant-floor support.

Subnet planning, address checks, MAC format helpers, and protocol notes for controls networks, OT devices, and integration work.

Networking Tool Index

IPv4 subnet planning, range checks, address classification, MAC format inspection, and industrial Ethernet reference notes for plant-floor troubleshooting.

Live calculators
Subnet CalculatorCIDR CalculatorIP Range CalculatorBroadcast AddressUsable Host RangeWildcard MaskBinary OctetsIP MembershipMAC Address HelperEtherNet/IP HelperIndustrial Ports

Subnet Calculator

Calculate network, broadcast, usable host range, subnet mask, wildcard mask, and binary octets.

CIDR
192.168.1.0/24
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255
Network address
192.168.1.0
Broadcast address
192.168.1.255
Usable range
192.168.1.1 - 192.168.1.254
Total addresses
256
Usable hosts
254
Address type
Private IPv4
Common RFC1918 private address space used heavily in OT and plant-floor networks.
Classful class
C
IP binary
11000000.10101000.00000001.01100100
Mask binary
11111111.11111111.11111111.00000000
Network binary
11000000.10101000.00000001.00000000
Broadcast binary
11000000.10101000.00000001.11111111

CIDR / Host Sizer

Find the smallest IPv4 subnet that can hold a required number of usable hosts.

Recommended CIDR
/26
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Total addresses
64
Usable hosts
62
Spare hosts
12

Sizing is based on usable IPv4 host capacity before VLAN, growth, routing, and addressing policy decisions.

IP Membership Check

Confirm whether a device address belongs to a subnet and whether it is a usable host address.

IP
192.168.1.25
Subnet
192.168.1.0/27
In subnet
Yes
Usable host
Yes
Network
192.168.1.0
Broadcast
192.168.1.31
Usable range
192.168.1.1 - 192.168.1.30
Address type
Private IPv4

IP Range Calculator

Count addresses and identify the smallest CIDR block that contains a start/end range.

Start IP
192.168.1.10
End IP
192.168.1.20
Address count
11
Minimal containing CIDR
192.168.1.0/27
Containing network
192.168.1.0
Containing broadcast
192.168.1.31
Start decimal
3232235786
End decimal
3232235796
Start binary
11000000.10101000.00000001.00001010
End binary
11000000.10101000.00000001.00010100

MAC Address Helper

Normalize MAC address formats and inspect multicast/local administration bits.

Colon format
01:00:5E:00:00:FB
Hyphen format
01-00-5E-00-00-FB
Cisco format
0100.5e00.00fb
OUI prefix
01:00:5E
Type
Multicast
Scope
Globally administered
First octet bits
00000001

Multicast MAC frames are used by many discovery, I/O, and time protocols.

EtherNet/IP Helper

Practical checks for Rockwell and other CIP-based device connectivity issues.

Confirm IP address, subnet mask, gateway, and VLAN before blaming the PLC or adapter.
Check duplicate IPs, link speed/duplex, managed switch port errors, and storm-control counters.
For EtherNet/IP I/O, verify UDP 2222 reachability, multicast handling, RPI load, and connection limits.
For explicit messaging and browsing, verify TCP/UDP 44818 and name resolution or path routing.
Capture both sides of a managed switch span when symptoms only appear under production load.

Industrial Protocol Quick Reference

Common ports and traffic notes for controls-network triage, firewall review, and packet captures.

EtherNet/IP

TCP/UDP 44818, UDP 2222

Explicit messaging normally uses 44818. I/O traffic commonly uses UDP 2222.

Modbus TCP

TCP 502

Client/server register traffic. Watch unit ID, word order, and firewall rules.

OPC UA

TCP 4840

Common default endpoint port. Certificates, hostname resolution, and time sync matter.

PROFINET

UDP 34962-34964, EtherType 0x8892

Discovery and real-time traffic may not route like normal TCP/IP services.

EtherCAT

EtherType 0x88A4

Layer 2 fieldbus traffic. Typical troubleshooting is adapter, cable, topology, and timing focused.

SNMP

UDP 161/162

Useful for managed switch diagnostics, traps, interface counters, and topology evidence.

PTP / IEEE 1588

UDP 319/320

Precision time traffic. Boundary clocks, transparent clocks, and VLAN treatment can matter.