Port 1745

[Thomas Linder Puls]

One of my collegues says that when the Vault client starts is opens port 1745 to some destination. This port is blocked by the firewall but vault seems to work anyway.

What is this?
It worries us that vault seems to contact third part.

[sterwill]

I've never heard of that happening, and I wrote most of the networking code on the client. Vault uses the .NET framework classes to establish all of its connections. Each type of connection falls into one of two classes: the first is SoapWebRequest (used for most client to server and admin client to server communication), the second is HTTPWebRequest (used for downloads of files only). Each of these objects allows us to set a URL, which may include a port number, but unless the user types "1745" into his connect string, we will never set that port number on these objects.

The Vault client never tries to send any information to ports other than 80, 443 (when SSL is checked) or the port the user types in the login server string. However, the libraries we call will automatically (in some cases) negotiate proxy authentication or do other proxy things, which may be what you're seeing.

This link explains the Microsoft ISA Proxy Firewall Client Control Channel, which listens on UDP and TCP ports 1745. It appears this connection is used to have the proxy server do some DNS lookups on behalf of the client and other things. If you're not running an ISA proxy, some form of packet analysis may tell you exactly what's happening.

[Thomas Linder Puls]

Thank you