KB54846
Published: March 7, 2007
Revision: 2.0

Default gateway configuration on primary port may affect secondary port communication on PAC controllers


Applies To:

SNAP-PAC-S1
SNAP-PAC-R1
SNAP-PAC-R2

Versions Affected:

Problem is found in firmware version: R7.1h
Problem is resolved in version: R8.0a

Resolved In Version:

Problem is resolved in version: R8.0a


Symptoms:

If a PAC controller has a default gateway configured on the primary Ethernet port, and the secondary port with an open socket becomes disabled, it will no longer be able to communicate through the secondary port, even if the port is re-enabled.

For example, a controller with:

    Primary IP address: 10.0.0.1
    Primary Subnet Mask: 255.255.255.0
    Primary Default Gateway: 10.0.0.10

    Secondary IP address: 192.168.0.1
    Secondary IP address: 255.255.255.0
    Secondary Default Gateway: 0.0.0.0

If the controller is communicating to an I/O unit with an IP address of 192.168.0.2, it is sending information through the secondary Ethernet port. If the secondary port is disconnected, the information for this I/O unit is routed to the primary port, to the default gateway. The default gateway discards the information because the IP configuration does not provide a route from the primary port to the destination address.

Even after the secondary port is re-connected, information continues to be routed through the primary port until the secondary port’s open socket is closed and reopened.


Workaround:

Do not configure a default gateway on either Ethernet port interface.


Resolution:

Opto 22 has resolved this issue.


Questions?

Contact: Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
Email: support@opto22.com


DISCLAIMER

This Opto 22 Knowledge Base ('OptoKB') article is intended to provide general technical information on a particular subject or subjects and is not an exhaustive treatment of such subjects. Accordingly, the information in this OptoKB article is not intended to constitute application, design, software, or other professional engineering advice or services. Opto 22 may modify the OptoKB articles at any time. Before making any decision or taking any action which might affect your equipment, you should consult a qualified professional.

OPTO 22 DOES NOT WARRANT THE COMPLETENESS, TIMELINESS, OR ACCURACY OF THE DATA CONTAINED IN THIS OPTOKB ARTICLE AND MAY MAKE CHANGES THERETO AT ANY TIME AT ITS SOLE DISCRETION WITHOUT NOTICE. FURTHER, ALL INFORMATION CONVEYED HEREBY IS PROVIDED TO USERS 'AS IS.' IN NO EVENT SHALL OPTO 22 BE LIABLE FOR ANY DAMAGES OF ANY KIND INCLUDING DIRECT, INDIRECT INCIDENTAL, CONSEQUENTIAL, LOSS PROFIT, OR DAMAGE, EVEN IF OPTO 22 HAS BEEN ADVISED ON THE POSSIBILITY OF SUCH DAMAGES.

OPTO 22 DISCLAIMS ALL WARRANTIES WHETHER EXPRESSED OR IMPLIED WITH RESPECT TO THE INFORMATION (INCLUDING HARDWARE, SOFTWARE, AND/OR FIRMWARE) PROVIDED HEREBY, INCLUDING THE IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, MERCHANTIBILITY, AND NON-INFRINGEMENT. Note that certain jurisdictions do not sanction the exclusion of implied warranties: thus, this disclaimer may not apply to you.

Copyright © 2018 Opto 22. All rights reserved.