ScommDll doesn't work because of firewall software

FAQ #100323

You can't connect over any channel to a PCD by using the SCommDll . The software firewall softwares "Zone Alarm Security", "Windows Defender" or "Bitdefender" block the SComm funktionality on PC's running MS XP.


If the ScommDll is launched, the PC won't react on key strikes for more than 40 sec. After this time, an error message is displayed saying "SCommDll error, Socket not installed or wrong server IP number".

The software firewall "Zone Alarm Security" blocks the ScommDll (The SCommDll communicated to the SCommDrv over an IP stream on port 7000 that is blocked).

Zone Alarm must be uninstalled; only deactivating won't work in most cases. This phenomenon was only observed on Windows XP. On W2k it seems that the ScommDll works also with ZoneAlarm activated.
In case the Bitdefender is used either disabling or appropriately configuring should help.


  • The behavior descripted above does also apply to many other Personal Firewalls (aka Desktop Firewalls, Internet Security Suites etc.). So if socket communication does not work, these security tools should be checked.
  • Most Personal Firewalls can be configured by so called "rules", which allow to open certain ports for one or more applications. So instead of totally disable or uninstall der firewall software, it may be a better solution to define apropriate firewall rules which allow SCommDrv to communicate anyway.
    For the relevant PG5 parts SCommDll.dll and SCommDrv.exe to work the TCP port 7000 needs to be enabled on the local host!


Software (except PG5) / SCOMM

Communication / Ether-S-Bus

PG5 2.0 / Profi-S-Bus

PG5 2.0 / Serial-S-Bus

PG5 2.0 / Modem

Last update: 28.05.2015 03:03

First release: 18.02.2005 11:24

Views: 12871

The requested software / document is no longer marketed by Saia-Burgess Controls AG and without technical support. It is an older software version which can be operated only on certain now no longer commercially available products.