I have a MySQL database running on my raspberry pi.
To access it I use dynamic DNS (duckdns) when I am outside of my network, but I would like to access it with same dynamic domain name when I am inside my network. However it is not working and I always get connection refused.
I would like somehow enable it so I do not have to change in app.config MySQL server address from my dynamic domain to localhost when I am inside my local network.
You'll need a gateway router that supports NAT hairpinning. Many consumer-grade units (and some supposedly commercial-grade equipment) doesn't support this. Either yours doesn't, or you need to find an option to enable it.
When you try to connect to the public IP address from inside the network, the router probably assumes that you want to connect to the router itself.
My cable modem's built-in router at home understands how to do this. When I access my server from the laptop, and connect to the public IP from inside, the router (inside the cable modem) does a transformation on the packets so that my server sees my connection coming from the router's IP address, not my laptop's IP address.
This is what has to happen, because when the server responds, it will respond to the machine that connected to it. If it responded to the laptop's address, the laptop would reject the traffic, since it would be coming from ther server's internal IP, which is not the IP address I connected to. So, it responds to the router, which does a second transform on the packet address, replacing the server's internal IP with the external IP. Remembering the session from previous traffic, the router then sends the packet back to the laptop.
Ultimately this setup can't possibly work for you without the complicity of your router, which may not have that capability.
Some routers, however, have a DNS proxy that will allow you to create static entries. My former DSL modem could not hairpin NAT connections, but it had a way to create DNS entries that would be used to respond to internal DNS queries for a specific host... with a different IP than the one that DNS otherwise provided. That's an alternative workaround if the router supports it.
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I am doing a code based load balancing i.e. on first request to the main server, it returns an address, to which the browser will open a persistent conncection using (wss) websocket. But, due to compatability with my mobile app, i'm returning a public DNS of aws instance, Ex: ec2-35-154-101-63.ap-south-1.compute.amazonaws.com which works fine in the mobile app. The browser however is refusing the connection because the address of websocket is not matching the parent domain. Are there any options to fix this other than using a Wesocket address from the same domain.
Edit: I had no choice rather than return a subdomain address for the websocket connection.
You are connecting to a URL that does not match the name in the SSL certificate.
You have two choices, either map the domain name to the instance or (not recommended) issue a certificate that matches the URL that you are using (ec2-35-154-101-63.ap-south-1.compute.amazonaws.com)
The correct approach is to specify the A address (IP address) in your DNS server for the EC2 instance so that requests for your_domain_name resolve correctly and then USE that URL and not the EC2 instance DNS name. You cannot specify the AWS URL for https as the SSL certificate was not issued to that identity.
I am using a software - (Ingress) by FingerTec which uses mysql database.
Some setups of this system are only using a single installation - consisting of a mysql server and a client locally on the same machine.
I have been having issues since I started to use the software when it is installed on a user's laptop/PC. The problem is that frequently when running the mysql server and client, a window pops up asking for the local IP address and port (127.0.0.1 and 3306 by default). To continue using the software, one needs to run IngressDB installer where you need to 'Update Connection' by giving the root user and pass for mysql and then 'Upgrade Database' to refresh the database for any new settings. After this step the software runs fine.
Yesterday I managed to simulate this issue by changing the static IP on my laptop while connected directly to one of their Access Controllers. I had to re-Run Ingress DBinstaller.
Now my question is this:
When using your machine(laptop/pc) it is normally getting IP add, def GW, Subnet etc from a dhcp server therefore there is no guarantee that you will always get the same IP leased unless there is a reservation to the machine's mac address.
As described earlier - when ever there is a change of IP address leased from DHCP, a window pops up showing the loopback address 127.0.0.1 and the mysql port 3306. So it never shows the local IP address (ex. 192.168.1.100). So I was thinking - why is the loopback IP not enough for mysql client/server as this stays the same forever.
Is is normal that software using mysql database server requires a static local IP on the machine hosting it? I am referring only to instances where both mysql server and client reside on the same machine.
I appreciate your thoughts about this and maybe any other way I can get around this apart from making an IP address reservation in the DHCP server. Setting a static IP address manually on the LAN adapter is no solution for me as this would limit the machine to connect only to a certain network and cannot be used at other places.
If the client is the same local machine as the server, the MYSQL server specifically does not need a static IP because it pretty much already has one: 'localhost' or '127.0.0.1'. If the client is not on the same machine as the server, the server would need a static IP.
If the machine is acting as a server for other content, yes, it would need a static IP. If you're doing this at home, chances are that your access point will let you configure it for a static IP.
I created successfully a apache server but I dont want to connect to it by typing 192.168.0.102, I want a normal url like www.google.com. How can I do that? I went to httpd.conf and found the ServerName line but setting it to something like www.mysite.com doesnt seem to work. I also tried to use my external ip(https://www.whatismyip.com) as server name but it doesnt connect. It only works if I try to connect to 192.168.0.102 or localhost. How do i solve this? Thanks
There are three basic things you need to know.
Virtual name hosting
HTTP allows multiple websites to be hosted on the same IP address and port. The client uses the Host request header to tell the server which site it wants to get data for.
ServerName is used as part of this.
… but the client needs to know how to send a request to the server first.
DNS
When a client makes a request to a server, it uses the IP address of the server in order to allow it to be passed over the network (or networks) to it. It is the address.
IP addresses are sequence so of numbers, which aren't very friendly for humans to work with.
DNS translates friendly names (like www.example.com) into IP addresses.
The client has to look up the name to find the IP address. It normally does this through the main DNS system, and in order to get your name linked to your IP address you will need to find a domain name registrar and pay them.
It is also possible to set up DNS at a local level on a private network, and on a computer-by-computer level using a hosts file.
Routing
The IP address of the server has to be routable from the computer the client is running on.
192.168.0.102 is a private address, accessibly only on the same LAN. To make it accessible to clients on the Internet you need to either:
Set up your router to use port forwarding and then use the Internet facing IP address of the router (which https://www.whatismyip.com tells you) or
Give your computer a public IP address and configure your router to route traffic to it (this generally isn't possible on consumer grade routers).
In short, you can't. 192.168.0.102 is not accessible from the Internet it is internal IP.
But you have some alternatives, like if you like to access your computer from a hostname you can use dynamic DNS servers.
Or you want to test your code on a spectacular domain, you can add 192.168.0.102 with a domain to your hosts file, then only you can use this domain with your local computer.
But, If you really want to serve some content to the Internet from your local computer you have to find a DNS server service (like cloudflare) to point your domain to your public Internet ip not to 192.168.0.102.
You configure the virtual host and set the server name to the domain name you want. After that, Apache will check the requests and will use that virtual host if a request was made for that domain name. In order for that to work, that domain should point to your IP address where the server is running.
If you want to test if the configuration works, edit your /etc/hosts file and add that domain name to 127.0.0.1. After that you will be able to access to that virtual host if you try to access to that domain name from your browser.
More info here : https://httpd.apache.org/docs/current/vhosts/name-based.html
Assume that there is a web-page called whatisyourip.com and that I have a web-page called changeip.com. A user wants to enter the site whatisyourip.com through changeip.com. Normally, changeip.com would be a proxy server so the user can hide his ip address. That's how users reach forbidden web-pages in their countries. But I want to ask, is there a way to show a different ip address to whatisyourip.com while connecting it through changeip.com without using it as a proxy server?
is there a way to show a different ip address to whatisyourip.com while connecting it through changeip.com without using it as a proxy server?
Short answer: Yes. Make changeip.com a VPN server and assign different IP addresses to those VPN clients. Ensure they send all traffic through the VPN. This usually involves modification of the local routing table on the VPN client workstations for everything to work correctly.
Longer answer... There are several reliable ways to hide IP addresses of TCP sessions...
HTTP Proxy - you already described this situation
Network address Translation - this doesn't sound likely in your scenario
VPN Tunneling - Possible solution instead of HTTP proxy, even if it's something as simple as an SSL VPN. Depending on your constraints, this could also be a viable option.
You can't. TCP connections require a 3-way handshake. You can certainly send a SYN packet to the server to start the process, then change your IP address. but when the site responds with the 2nd-stage of the handshake (SYN+ACK), that packet is now going to your old IP address and your system will drop it - it has no idea that the server is responding to something that was started on the old IP.
You could try something like the Tor network, which offers end-to-end encryption of traffic and cloaking of origins, but it's not something I'd consider "reliable".
Not unless you spoof your IP, in which case the response will go to the forged IP. So no.
Is there a performance difference between TCP connections to:
localhost / 127.0.0.1
a domain which resolves to the local machine
Or more specifically, do the latter connections go through the loopback device, or over the actual network?
The reason I'm asking is I'm thinking about changing database settings in many PHP apps so they use a full domain instead of localhost. That way we could more easily move the database to a different server, if the need arises.
This is implementation and operating system dependent. On Windows, anything connecting to a local IP address, even if it is an outside-facing IP, will go over loopback. This is a documented problem for applications such as packet sniffers, because you can't sniff the loopback. (Windows doesn't treat loopback as a "device" -- it is handled at the network level.) However, in this case it would work in your favor.
Linux, in contrast, will follow whatever you have in your routing table, so packets that are destined to your local machine will go to your local machine over the network if the routing table isn't properly configured. However, in 99% of the cases the routing will be configured properly. Your packets won't go over the loopback device, but the TCP/IP stack will know that you are contacting a local IP and it will virtually go out and back in the proper ethernet device.
In a properly configured environment, the only bottleneck for using a domain name would be DNS resolution time. Contacting an outside DNS can add additional latency into your configuration. However, if you add in the domain name into your /etc/hosts file (C:\Windows\System32\drivers\etc\hosts on Windows), your system will skip the DNS resolution phase and obtain an IP directly, making this time cost moot.
That depends on how the names are resolved. The procedure is typically /etc/hosts first and then DNS if that fails. If localhost is in your /etc/hosts, putting whatever.wherever in the file as well will make it resolve with the same speed.