> Source: [sk114018](https://support.checkpoint.com/results/sk/sk114018) # sk114018 - Unable to connect to Skype application using port 5061 with pre-defined TCP service | Property | Value | |----------|-------| | Solution ID | sk114018 | | Date Created | 2016-10-21 | | Last Modified | 2018-11-21 | | Technical Level | Advanced | | Products | Security Gateway | | Versions | R82.10, R82, R81.20 | | OS | Gaia | ## Symptoms - * Unable to connect the Skype application when the predefined TCP TLS service port 5061 is defined in the security policy rule. * SmartView Tracker logs shows the traffic is allowed, but Skype fails to sign in (stuck at "Contacting server and signing in"). * There are no kernel drops found on the Security Gateway. * Packet captures shows that 3-way handshake happening along with the data transmission. There is bidirectional traffic, going all the way through the Security Gateway to server and back, however unable to login to the Skype application. ## Cause 5061 is defined for SIP over TLS services. In the pre-defined service of SIP port 5061, there is a protocol handler, i.e protocol SIP_TCP_Proto (configured in the SmartDashboard \> Service Properties \> Advanced \> Protocol Type). When a packet arrives to the Security Gateway and matched on a rule with this service configured, the special code for handling SIP will take effect. ## Solution This solution requires authentication. Please log in to view the full solution. --- # Agent Instructions This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products. ## Navigating This Knowledge Base - **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt) - **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml) - **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}` - **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content