Deep inspection firewalls, also known as deep packet inspection (DPI) firewalls, analyze the content of network traffic beyond basic header information, inspecting the payload of packets to enforce security policies, detect anomalies, and filter out malicious data. While this provides enhanced security, deep inspection can interfere with FTP uploads and downloads due to the unique characteristics of the FTP protocol. […]
Carbon Black is security software that can block your application from running unless you whitelist it. Here’s a description of how a Chilkat user discovered that Carbon Black was the cause of his PowerBuilder application not working. We figured out why the executable could not retrieve a token from Box. It was not a firewall/network issue, the application was being […]
If something on the client-side is blocking communications, such as a hardware or software firewall, or anti-virus, then it may be that a TLS connection is established, but then trying to read the 1st message from the server gets blocked. When this happens, the contents of the LastErrorText look like this. (The LastErrorText for a successful connection is shown below.) […]
The following error can be caused by firewall restrictions. I do not know the specifics of the firewall restrictions, but the TLS connection completes successfully in the prior call to Chilkat.Rest.Connect(). In other words, the TLS handshake completes successfully and then the firewall closes (or blocks) the connection. ChilkatLog: FullRequestFormUrlEncoded: DllDate: Jul 24 2019 ChilkatVersion: 9.5.0.79 UnlockPrefix: Start […]
The following error can be caused by a firewall blocking the iPAD/iPhone wifi connection: … connect successful (1) clientHelloMajorMinorVersion: 3.1 buildClientHello: majorVersion: 3 minorVersion: 1 numRandomBytes: 32 sessionIdSize: 0 numCipherSuites: 10 numCompressionMethods: 1 socketErrno: 32 socketError: Broken pipe Error sending on socket send_size: 58 Failed to send TLS message. Failed to send ClientHello Client handshake failed. Failed to connect to […]
The following Chilkat FTP2 error was found by a Chilkat customer to be caused by firewall restrictions. I do not know the specifics of the firewall restrictions that caused the error, but the LastErrorText (with all customer information removed) is reproduced here to help identify this problem in the future. The important point is to see that the SSL/TLS handshake […]