difference between bind-web-address and volttron-central-address - volttron

I entered information for the volttron central instance as follows:
cat ~/.volttron-master/config
bind-web-address =
vip-address = tcp://
instance-name = "central tcp://"
volttron-central-address =
What is the difference between bind-web-address and volttron-central-address?
In my opinion, the former is required for the web service, and the latter is for entering the address of the instance to control this instance.
Can the port number be the same?

The difference is context. Bind web address is opening a port on the machine that is going to be the web server. The volttron central address is used as the location to look for the web server. I hope that makes sense.
They should be the same when your Vc and VCP are on the same instance.


Can't POST credentials on OCN client

I have a problem with OCN-client.
When I call POST http://host/ocpi/2.2/credentials, response:
Role with party_id=ABC and country_code=ES not listed in (truncated)...
Means that I have to register our company?
How I can do it?
Yes, the client will not accept the credentials handshake if you are not already listed in the registry. Running the registry locally will create a new network only existing on your local development environment. To do this, you would also need to point the OCN client to your local network in its configuration. This is good during development, though there will be no other MSPs/CPOs to interact with out of the box (see https://bitbucket.org/shareandcharge/ocn-tools for how you could do that yourself). Once you are ready, you could then access our public test environment via your local OCN client (the default configuration values point to it), or connect to one remotely.

Access host variable from virtual machine

I have a react-app, I set up my app to run on a custom url using the HOST variable when starting the app, something like:
"scripts": {
"start": "HOST=my-local-website.com ..."
I need to access this url from a windows virtual machine to test it on IE11, before setting up the HOST variable I was able to access it simply from my IP address (192.168.X.XX:3000), having changed the HOST variable this doesn't work anymore.
Does anyone know how I can access it from a virtual machine?
Thank you in advance
I suggest to set environment variables in separate .env file like described in dicumentation.
In .env file set HOST=my-local-website.com to change host (it's unclear why official doc recommends prefixing all env variables with REACT_APP_)
Web site name my-local-website.com mapping to IP address of server (192.168.X.XX:3000 in your case) is done using DNS. This relate to networking and not to frameworks you use. So to be able to access your site by name you have to establish mapping between name of the site and IP address
I terms of DNS this mapping will look like
my-local-website.com A 192.168.X.XX
But for testing purpuses you can use simplified approach (I don't think that you have established DNS server in place). On Windows you can use hosts file which is located in C:\Windows\System32\drivers\etc folder. File is named hosts. Open it with any text editor (like notepad) and add string
192.168.X.XX my-local-website.com
IP address goes first, name last. Dont include port number (:3000) as it not related to DNS. hosts file should be changed on you test (client) PC, not on the PC where your app run.
You may also modify hosts on PC where you app runs to check if host has been configured correctly.
To check that everything is correct you may use ping like this
ping my-local-website.com
IP address should be printed if you configured everything correctly.
If you run your app on Windows host there may be problem with firewall configuration. If your app open on the same PC where it is started but not on another PC, most probaly that firewall blocks traffic. It can be WIndows Firewall or antivirus software if you have any.

Not able to access a port on ec2 instance for an Angular app

I am working on an angular app using the angular cli to set things up. Running the ng serve command spawns a server at this address <my_ec2_host_name>:4200. When I try to access the page on the browser it doesn't work (connection timed out error). I believe this is because of security reasons so I added the following rule to my security groups for the ec2 instance:
Port 4200 should now be accessible but I still can't get the page to load. Can someone think of how to get this to work?
Start angular with below command.
ng serve --host= --disable-host-check
it will disable host check and allow to access with IP
You can set up the host option like this:
ng serve -host
The steps you are doing are correct for opening a port via Security Groups in the EC2 console. Make sure you are modifying the correct security group, and make sure that your changes have been saved.
Your container may have additional firewalls in place, so you will want to check the OS documentation. For Example, RHEL uses iptables as a further security measure: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/sect-Security_Guide-IPTables.html.
That looks correct. Are you sure that your server is running and listening for connections?
You should ssh to that server and verify that the page can be loaded locally. Eg:
curl http://<YOUR HOST IP ADDRESS>:4200
eg: curl
You should be careful to use the public ip address (eg: IPv4 Public IP when you're in the EC2 console). I've run into problems in the past where I've got a server listening on one IP address (often localhost) and not the public ip address.
Also maybe a problem: Is your host inside a VPC of some sort?

expose local webserver behind dynamic IP

I've a simple webserver bound on on my machine which works as intended on local networks. By local network I mean to say, if my mobile or any other device is on the same network, it can access local webserver by going to the IP assigned to my machine and adding port 3000 to it. Eg
Now I've to expose it to the internet but not through some sort of 3rd party application like ngrok, localtunnel or browserSync. I know that these applications work perfectly, but since I've my own pet project of controlling home appliances, I don't want to rely on availability of 3rd party services. So the current state is, I cannot control it through the internet. Keeping in mind I don't have a static IP otherwise this would've been easier.
I already have a vps and a domain name assigned to it. I can send my currently allocated ip address (since it is dynamic), by using getifaddrs, to my server and keep track of it. But how do I expose my local server to the internet through it? Those 3rd party applications assign some sort of subdomains to each exposed server, and I'll be able to assign subdomains too, but I'm still not getting any way to expose the local webserver. Any help would be appreciated, thankyou :)
Step one, you need to expose your webserver at your internet access router.
Typically this requires you to configure port forwarding for (in your case) port 3000.
With this done, any client could access your service via (current external dynamic ip):3000
Step two, you need to dynamically map a fixed DNS name to your current dynamic ip. There are of course third party services (such as DynDNS) that would help you map yourfavoritename.dyndns.org to that ever-changing ip address.
If you want to do the latter without 3rd party, you need to have some static (web) server somewhere and could proceed as follows:
Clients visit http://www.yourstaticserver.example/ and that server redirects them to (current dynamic ip):3000.
Of course, for this to happen, your static server needs to know the dynamic ip and needs no find out about changes to it.
To this end, you could have your internal server contact the static server on a regular interval (such as once a minute), say, have it access http://www.yourstaticserver.example/some-secret-special-page and the static server always stores the REMOTE_ADDR of such a request (preferably with some authorization!) for its future redirections.
Actually, there is a step zero before step one: Be aware that exposing your server to the Internet means that you expose your server to the Internet. So I hope you have invested enough thought into security.

How to respond requests with the windows host file?

Using the windows host file located in
Is it possible to respond a request from an application like when it is offline(not connected to the Internet)? Could you please give an example of this is done.
The hosts file only lists aliases for ip-addresses. For example: foo bar foo.com bar.com
If that line is in the hosts file, then you can use the host-names foo, bar, foo.com and bar.com to reach the computer with ip-address
If the computer, or the service you want to reach on that address, is not online, you can't reach it no matter what you have in your hosts file.
If you are willing to map your local development environment to a domain name, you can edit the domain name in hosts file and map it to, which is the loopback address.
That way, any requests done to that particular domain will fallback to your local machine.
You can also assign different LAN/WAN IP addresses.
When your development phase is done, you can remove the entry.
I would not recommend doing so, stick with the localhost and just make use of that to test virtualhosts setup or some sort of domain based configurations.
If there is anything else I can answer, please don't hesitate to post further comments on my answer.
If you mean to respond to HTTP requests then you need a Web Server configured to respond to any host (or that specific host name) on port 80. If you are not using it for anything else IIS can do this1 – configure it to return 404 (not found) or some other relatively neutral fail response.
1 If IIS is already being used then things get much harder, later versions of IIS are more flexible either with a combination of using HTTP.SYS to allow other applications to respond to certain URLs or using different Web Sites in IIS (until Windows 7, or maybe Vista, only available on Server editions of Windows).