Accessing http url hosted on a VNet Peered VM from another VM - vnet

If I peer two Bastion VMs via VNet, and run a web application on one VM, will I be able to access its REST url from the other VM? Is there a charge involved for this type of access?
Sorry that I couldn't find it in me to understand all that jargon about ingress, egresss and gateways. I just want the simple answer to my question.

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Aws ec2 - Unable to consume http server from a different machine on the same network

Followed this tutorial to setup two ec2 instances: 12 . Creation of two EC2 instances and how to establish ping communication - YouTube
The only difference is I used a linux image.
I setup a simple python http server on a machine (on port 8000). But I cannot access this from my other machine; whenever I curl, the program kind of waits. (It might eventually timeout but I wasn't patient enough to witness that).
However, the workaround, I figured, was that you have to add a port rule via the security group. I do not like this option since it means that that port (for the machine that hosts the web server) can be accessed via the internet.
I was looking for an experience similar to what people usually have at home with their routers; machines connected to the same home router can reach out to other machines on any port (provided the destination machine has some service hosted on that port).
What is the solution to achieve something like this when working with ec2?
The instance is open to the internet because you are allowing access from '0.0.0.0/0' (anywhere) in the inbound rule of the security group.
If you want to the communication to be allowed only between the instances and not from the public internet. You can achieve that by assigning the same security group to both the instances and modifying the inbound rule in the security group to allow all traffic or ICMP traffic sourced from security group itself.
You can read more about it here:
AWS Reference

How to connect to Community Edition Databricks Cluster via Outside Public Address / Application

Can someone let me know if its possible to connect or PING a Databricks Cluster via its public ip address?
For example I have issued the command ping --all-ip-addresses and I get the ip address 10.172.226.115.
I would like to be able to PING that ip address(10.172.226.115) from my on-premise PC (or connect to the cluster with an application using the ip address?
Can someone let me know if that is possible?
That public IP is not guaranteed to be your cluster; unless somehow you've installed Databricks into your own cloud provider account, where you fully control the network routes, it would be connecting to Databricks managed infrastructure where the public ip would likely be an API gateway or router that serves traffic for more than one account
Note: just because you can ping Google DNS with outbound traffic doesn't mean inbound traffic from the internet is even allowed through the firewall
connect to the cluster with an application
I'd suggest using other Databricks support channels (i.e their community forum) to see if that's even possible, but I thought you're just supposed to upload and run code within their ecosystem. At least, for the community plans
Specifically, they have a REST API to submit a remote job from your local system, but if you want to be able to send data back to your local machine, I think you'd have to write and download from DBFS or other cloud filesystem

How to grant VPN access to my own OpenVPN without configuration files

I have created my own VPN service on one my VPS servers and logged in using the configuration files, i was wondering is there an easy/straight forward way to connect to my openvpn service for my community with a naive technical background.
Thanks,

Can't access port 7474 across Rackspace cloud servers

I've setup neo4j on port 7474 on a Rackspace cloud server. I want to access this server from another Rackspace cloud server (appserver) but the connection is refused.
I've tried enabling access for the appserver to port 7474 on the neo4j server using ufw:
sudo ufw allow from 22.234.298.297 to any port 7474
I can see this rule when I run 'ufw staus' but it doesn't seem to make any difference when I try to connect to the appserver. I can ssh between these two servers.
How do I open port 7474 between cloud servers on Rackspace?
(my apologies for this very basic question but rackspace support are not helping and I cant find rackspace specific information on this)
Glad, we could solve the problem (see comments on the question).
It so happens that Neo4j accepts only connections from localhost per default. When trying to gain access to Neo4j via REST API from an app server within the same network, one has to configure the Neo4j server to open up.
The neo4j-server.properties configuration file has a configuration key with org.neo4j.server.webserver.address. You have a couple of options here.
Grant app servers in the same local network to consume the Neo4j REST API
Grant everybody access and let the firewall handle it
For the first case, use the local ip address of the machine where Neo4j is running. Let's say your machines are connected via a private class C network. The machine with Neo4j has an ip 192.168.1.4 - that's the ip you want to enter as the value in org.neo4j.server.webserver.address, so your app server running in the same network with maybe an ip of 192.168.1.5 can make network requests that are being answered by the Neo4j web server.
For the second case, you enter 0.0.0.0 as value for org.neo4j.server.webserver.address to denote that you want to accept connections on all available ip addresses on that machine. In that case you want to set up your firewall to handle permissions who can talk to the server and who doesn't - even with authentication enabled.
Extra
In a production environment that requires high availability, one can use Neo4j's enterprise edition with a high availability cluster in a master-slave setting. I've used in with one master and two slaves. I configured the Neo4j servers that they can only be accessed from the proxy server that routes writing cypher queries to the master, and reading queries to the slaves. The proxy itself had a hardware firewall on it to ensure only specific app servers within the network have access to the Neo4j database.

Can I allow access to a site available only on LAN to another user connected to my computer?

So I know I can use ngrok to project a website I host on localhost to be available publicly. Can I do the same for another site, which is only available in the local network, but not hosted on my machine?
For example, there is a website hosted on http://testing.stackoverflow.com, which is a version of the website that's only available to people connected to the internal wifi, but I want to so my customer a new feature that's only available on that website, without making it available to everyone. The customer can only access it while somehow connected to my machine. Can ngrok or a similar tool do this?
You can use ngrok to expose any host, accessible to you, to the internet. See https://ngrok.com/docs#non-local.
You have already used ngrok to tunnel traffic between internet and your localhost. Similarly, if you want to expose a web server in your LAN, say 192.168.22.22, just execute ngrok http 192.168.22.22:80, instead of ngrok http 80.

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