Firewall applications for desktop PCs block network traffic and secure ports from incoming network traffic. ActiveSync uses the TCP protocol to transfer data between your PC and your Windows Mobile device - when a firewall blocks this transfer, the synchronisation fails.
To overcome this, you need to add the ActiveSync applications into the firewall applications list of exceptions - programs that are allowed access to the wider network or the internet.
In many cases this should be a straightforward process and in other cases there will be no issue as the firewall software automatically recognises the ActiveSync application and allows access - however some firewalls don't, such as:
- Sygate Personal Firewall
- TrendMicro PC-cillin Internet Security 2005
- Norton Personal Firewall
- Zone Alarm Security Suite
- McAfee Personal Firewall
- Windows Firewall
- BlackICE Firewall
In order to get ActiveSync working successfully with these firewalls, you will need to add the three ActiveSync processes to the firewall exceptions list:
(These are typically found in C:\Program Files\Microsoft ActiveSync).
Once added to the exceptions list of your firewall software, these three components of ActiveSync should then successfully connect your PC and Windows Mobile device for trouble-free syncing.
(In extreme cases, Inbound TCP and Outbound TCP ports used for communication may also need to be opened in your firewall configuration:
You may need to check your firewall user guide to check how to open ports for a particular application as this function is often hidden away to avoid accidental use.)