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Troubleshooting Connect issues involving and local ports

Question & Answer


Troubleshooting Connect issues involving and local ports



Connect 3.6.5 and newer uses the domain name that points to a machine's local IP address. There is an SSL certificate for the domain that allows Connect to make requests to the local machine through HTTPS.

If Connect cannot make a connection to (as of now, on Chrome, Firefox and Edge browsers), the Connect plug-in will not be able to launch.


1. Test that can be resolved by the DNS server.

On Linux/Mac OS X, run the following command:

# host

The expected, correct response is the following: has address

If the DNS server cannot be reached, you will see something like the following:

Host not found: 3(NXDOMAIN)

This usually occurs when the system is on a closed network, or accesses the internet through a restrictive proxy. See this KB article for more details on how to solve this: DNS cannot resolve for Connect

2. Test the connection to the default local Connect port

Connect listens in the local port range 43003-43013. Typically it ends up listening on the first available 43003.

On Linux/Mac OS X run the following command:

# telnet 43003

The expected correct response is a successful connection which would look like this:

Connected to localhost. 
Escape character is '^]'.
^] (Control+])
telnet> quit
Connection closed.

If there are issues you will get a response like this:

telnet: connect to address Connection refused
telnet: Unable to connect to remote host

This could indicate that:

  • Connect is not running
  • Connect is not current (3.6.5+)
  • The port is blocked locally either by virus protection software or a local firewall

3. Test for issues with an antivirus program (specifically Symantec)

While an antivirus like Symantec can block access to ports from the browser it cannot block access from the terminal.

With Connect running run the following command:


The expected correct response is an empty curly brace pair { }.

In Chrome Firefox or Edge enter the following URL into the address bar:

If there is no error and no port blockage you will again see { }.

If there is an error you will see a message such as Page Unreachable or Security Error. This indicates that Symantec is likely blocking Connect's local ports.

In this case the customer should have their IT team open ports 43003-43012 on localhost.

4. Consult other articles that involve

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Document Information

Modified date:
08 April 2020