987
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Configuring MODBUS TCP
Understanding MODBUS TCP, page 987
Configuring the Switch as the MODBUS TCP Server, page 988
Displaying MODBUS TCP Information, page 989
Understanding MODBUS TCP
Use Modicon Communication Bus (MODBUS) TCP over an Ethernet network when connecting the switch to devices such
as intelligent electronic devices (IEDs), distributed controllers, substation routers, Cisco IP Phones, Cisco Wireless
Access Points, and other network devices such as redundant substation switches.
MODBUS is a serial communications protocol for client-server communication between a switch (server) and a device
in the network running MODBUS client software (client). You can use MODBUS to connect a computer to a remote
terminal unit (RTU) in supervisory control and data acquisition (SCADA) systems.
The client can be an IED or a human machine interface (HMI) application that remotely configure and manage devices
running MODBUS TCP. The switch functions as the server.
The switch encapsulates a request or response message in a MODBUS TCP application data unit (ADU). A client sends
a message to a TCP port on the switch. The default port number is 502.
Multiple Request Messages, page 988
MODBUS and Security
If a firewall or other security services are enabled, the switch TCP port might be blocked, and the switch and the client
cannot communicate.
If a firewall and other security services are disabled, a denial-of-service attack might occur on the switch.
To prevent a denial-of-service attack and to allow a specific client to send messages to the switch (server), you can
use this standard access control list (ACL) that permits traffic only from the source IP address
10.1.1.n
:
interface Ethernet0/0
ip address 10.1.1.1 255.255.255.0
ip access-group 1 in
!
access-list 1 permit 10.1.1.0 0.0.0.255
To configure quality of service (QoS) to set the rate-limit for MODBUS TCP traffic:
interface FastEthernet0/1
ip address 10.1.1.1 255.255.255.0
ip access-group 1 in
rate-limit input access-group 101 8000 8000 8000 conform-action transmit exceed-action drop
Содержание IE 4000
Страница 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Страница 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Страница 108: ...104 Configuring Switch Clusters Additional References ...
Страница 128: ...124 Performing Switch Administration Additional References ...
Страница 130: ...126 Configuring PTP ...
Страница 140: ...136 Configuring CIP Additional References ...
Страница 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Страница 192: ...188 Configuring Switch Based Authentication Additional References ...
Страница 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Страница 274: ...270 Configuring SGT Exchange Protocol over TCP SXP and Layer 3 Transport Configuring Cisco TrustSec Caching ...
Страница 298: ...294 Configuring VLANs Additional References ...
Страница 336: ...332 Configuring STP Additional References ...
Страница 408: ...404 Configuring DHCP Additional References ...
Страница 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Страница 490: ...486 Configuring SPAN and RSPAN Additional References ...
Страница 502: ...498 Configuring Layer 2 NAT ...
Страница 559: ...555 Configuring Network Security with ACLs How to Configure Network Security with ACLs Creating a Numbered Extended ACL ...
Страница 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Страница 930: ...926 Configuring IP Unicast Routing Related Documents ...
Страница 956: ...952 Configuring IPv6 Unicast Routing Configuring IPv6 network 2010 AB8 2 48 network 2010 AB8 3 48 exit address family ...
Страница 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Страница 978: ...974 Dying Gasp ...
Страница 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Страница 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Страница 996: ...992 Ethernet CFM ...
Страница 1030: ...1026 Working with the Cisco IOS File System Configuration Files and Software Images Working with Software Images ...
Страница 1066: ...1062 Using an SD Card SD Card Alarms ...