"OUTBOUND" and "INBOUND" Sessions Information

Remote access systems assigned with a specific public internet address will be able to initiate "OUTBOUND" sessions to the internet. These internet addresses start with:

  • 198.81.193
  • 204.90.115
  • 192.86.32
  • 192.86.33

To ensure and enhance the security of the internet connections to the IBM Z® Dallas ISV Center remote access systems, IBM has blocked various ports from "INBOUND" traffic. This means, the mentioned addresses will NOT be able to accept "INBOUND" sessions from the internet to an IBM Z Dallas ISV Center remote access system on specified ports.

Blocked Ports

The following TCP Ports have been blocked for "INBOUND" traffic:

  • 25
  • 135
  • 139
  • 445
  • 2240
  • 2710
  • 3391
  • 3526
  • 3531
  • 3535
  • 4662
  • 6346
  • 6348
  • 6379
  • 6881
  • 6882
  • 7881
  • 8000
  • 8001

Important Notes:

  • If a session is initiated on one of these ports from an IBM Z Dallas ISV Center remote access system outbound to some other system on the Internet, traffic will be allowed to return to the port.
  • If you are using any of these ports, please update your application immediately so it provides services on a different port.
  • The port restrictions do not apply to remote access systems that have been assigned a private IP address on the IBM Z Dallas ISV Center VPN network.



If you have any questions, send us an email to zTech@us.ibm.com