Issue
Sigma communications may intermittently fail on Microsoft operating systems starting from Windows Vista due to changes in the default dynamic TCP/IP port range.
Product Line
Satchwell BAS & Sigma
Environment
- Microsoft Windows Vista
- Microsoft Windows 7
- Microsoft Windows 8 / 8.1
- Microsoft Windows 10
- Microsoft Windows Server 2008 / 2012
- Ethernet communications
- Sigma as part of an SBO/EBO front-end system
Cause
To comply with IANA (Internet Assigned Numbers Authority) recommendations, Microsoft increased the dynamic client port range for outgoing connections starting with Windows Vista. The new default range is:
- 49152 to 65535
This change affects Sigma, which uses port 49152 for communication between the Sigma server and controllers. The overlap can cause intermittent communication issues.
Resolution
Option 1: Reserve Sigma Port
Use SE Legacy Port Reservation to reserve port 49152 for Sigma, preventing conflicts with dynamic port allocation.
Option 2: Redefine Dynamic Port Range
Modify the dynamic port range to avoid overlap with Sigma’s communication port. Recommended range:
- Start Port: 50000
- End Port: 65535
Use the following netsh commands to view and set port ranges:
View Current Dynamic Port Range
netsh int ipv4 show dynamicport tcp
netsh int ipv4 show dynamicport udp
netsh int ipv6 show dynamicport tcp
netsh int ipv6 show dynamicport udpSet New Dynamic Port Range
netsh int ipv4 set dynamicport tcp start=50000 num=15535
netsh int ipv4 set dynamicport udp start=50000 num=15535
netsh int ipv6 set dynamicport tcp start=50000 num=15535
netsh int ipv6 set dynamicport udp start=50000 num=15535
Note:
- Minimum range: 255 ports
- Minimum start port: 1025
- Maximum end port: 65535
To replicate Windows Server 2003 behavior:
netsh int ipv4 set dynamicport tcp start=1025 num=3976
netsh int ipv4 set dynamicport udp start=1025 num=3976
Additional Considerations
- Firewall Configuration: Ensure internal firewalls allow traffic in the dynamic port range (49152–65535) to avoid RPC communication issues.
- Exchange Server 2007: On Windows Server 2008, the default port range is 1025–60000. Adjust accordingly if Sigma is deployed alongside Exchange.
