linux add ip route then restore the old routes - linux

I have a small software which connects to a pptp VPN server. It adds a route on if-up.d which routes all traffic through the VPN ip route change default via $PPP_LOCAL dev $IFNAME
Problem is that when I disconnect the VPN/close the software, the pptp connection closes but the routes are not restored. I've also added a delete route command in the if-down.d section to delete this route ip route del default via $PPP_LOCAL dev $IFNAME but my internet stops working. I have to "Disable/Enable networking" to have internet again.

This is a guess since I have no way of testing it, but instead of changing the default-route, could you just add another with a lower metric?

Related

Node.js only allow connections with specific VPN

I am trying to make a simple Node.js app with the express npm package to only allow if you are connected to a specific VPN. Here's an example:
I am connected to VPN exampleVPN and I am looking at http://localhost:8080, which sends me a 204 response.
But:
If I am not connected to exampleVPN and go to http://localhost:8080, I get a 401 response.
I'm just starting out and I am not sure of the strategy to go with here.
My first guess is to only allow incoming requests from a specific VPN server through a middleware by whitelisting the VPN's IP but that seems janky and could bring up some issues down the line if the VPN's IP changes for whatever reasons.
Thanks in advance.

nodeJS alternative to IP-Adress or localhost? Avahi-daemon

I am using Nodejs with the express, bcrypt and body-parser packages on an ubuntu linux system.
Everything works fine so far.
However, I´ve been wondering if there is an easier way to connect to my website.
Until now, I have to type in my IP adress, e.g. https://XXX.XXX.XXX:3000 to actually see the content.
I´ve already tried avahi-daemon but did not get it work. Whenver I try 'hostname.local' I get the same error: Firefox is unable to connect to server.
However, using the IP-Adress: https://XXX.XXX.XXX:3000 works.
I would like to access my NodeJS sever with something similar to: computername.local
FYI: I just want to use it in my local network at home.
Does anybody have any idea how to get this work?
You have a couple choices. The easiest,if available, is probably to setup your home router to always assign it the same IP address (how to do that will vary based on your router). If your router has it available, you could also set a host name for it there in DNS settings.
If your router doesn't have DNS settings available, then you can add a line to each of your home computers /etc/hosts file (if memory serves Windows has it in C:\etc\hosts). Let's say the IP you give the server is 172.16.1.11, your hosts entry would be
172.16.1.11 computername.local
You could also setup your own DNS server in your house, possibly even on the same machine as has your node app, and then configure it to handle the one address before forwarding DNS requests for others to your ISP but that seems like overkill if you have just one app.

How to create a NodeJs server accesible from an external connection without port forwarding

I'm currently working on a project where I use a raspberry pi as a server for a home automation server. It works fine on my local network but if I want to use it from an external computer I need to forward the used port on my router.
I'm trying to find a way to make http(s) gets to the server without having to forward the port on the router. I want this because if I would install the system at someone's place (a customer maybe in the future) I don't want to have to access their router.
I've tried using SSL and https but I ran into the same problem.
Is there any way this is possible or is it a lost case?
PS I can't use port 80 since it is already in use.
Thanks in advance
There are two ways to get to the result you want:
Port forwarding, which you've dismissed
Giving the raspberry pi it's own public IP address (which requires a public IP address and access to the router to configure the traffic routing, which you've dismissed).
So let's go back to port forwards.
Most consumer routers these days support NAT traversal via uPNP.
You can use the nat-pmp module to reqest the the router forward a port for you, without having to have direct access to the router.

How to share web application on linux?

I host a web application on my laptop and I access it using 'localhost:9080/abc.com' and lets assume my IP is '192.168.10.20'
Now, I want my colleague to access this web application from his system 'web browser' by typing in '192.168.10.20:9080/abc.com'
As laptop is owned by 'company' I cannot install (or) use any third party softwares
How can I manage this on RHEL 6?
Assuming you're on the same network (LAN) then a client who connects to 192.168.10.20:9080 should have no problems (assuming the web aplication also listens to requests other than localhost).
If abc.com is just an "alias" you set up in your hosts file then no other person than yourself will be able to use abc.com to connect to 192.168.1.10.20, unless they have the same alias in their hosts file.
If you purchased a domain abc.com and set up it up to redirect to 192.168.10.20 it should work. But usually there are delays associated with updating a DNS so the time it takes for abc.com to be updated can take even a day.
Now if you have your colleagues on a different network (for example they want to connect from their homes when the laptop is connected to the internet at your place) it won't work with a bit of fiddling. Basically, when they try to connect the router gets a request from the client to connect to port 9080, but the router doesn't know what to do with it so nothing happens. You have to set up port forwarding in your routers settings so that all incoming traffic on port 9080 gets sent to 192.168.10.20.
And when they try to connect that way, they can not use the 192.168.10.20 ip adress, because it always refers to a adress on the local network. They have to use your external ip adress (google what is my ip adress).

xampp server (How to get up and running)

I've been developing locally on a little ubuntu netbook with xampp for about 7 months. Two weeks ago I got a computer I'd like to use as a server. I've installed the latest Ubuntu distribution and xampp, moved all my files over, and forwarded port 80. I've also got a domain name from dyndns.com which is being updated by a client which runs in my router (a Netgear WGR6154 v8).
Now, when I try to access my server by typing in the address I got from dyndns.com the browser loads until it timesout. I can access everything locally using localhost as the address so I believe xampp is running, just unable to connect with the internet.
In order to be able to view my files over the internet what should I do next?
Thanks to all in advance...
[I'm starting a bounty for the first person to help me get my files successfully online]
You have a combination of issues here, and that is something of a problem. Each issue is complex in an of itself. Here is what I would recommend to get you going for certain.
First verify that you can surf the web from your server. This will confirm that you have a working ethernet interface.
Step 1 make sure that XAMPP, and your files are viewable from your home network. I assume you are using something like 192.168.1.X for your network and perhaps your server is 192.168.1.10
Go to another computer in your house and type http://192.168.1.10/ and see if you can see your files. If you can then you know that the server is properly configured and XAMPP is working.
Then add an entry to your hosts file to resolve yourdnsrecord.com (or whatever your dyndns record is) to your private ip address. Then when you type yourdnsrecord.com into a browser from that computer you should still get your files. This will rule out your server being improperly configured to listen for that domain name.
Next you need to test to see if there is a firewall problem. To simplify this, first remove your home router from the equation. Instead, place your new server directly onto your internet connection. (assuming you can). This way, you do not need to have NAT or firewalls properly configured. Your dyndns name should map to a public IP and your server should then have that IP and be connected directly to the Internet. If you have your server directly connected, and the command ifconfig from the root prompt returns the same public IP address that your dynamic dns record is point to, then it should work.
It will make your life easier if you have an iphone or some other way to test how your network is seen from the Internet.
If your public IP as shown by ifconfig is different than the IP record in your dyndns account, then your dynamic dns update script is broken. manually set the IP, and see if things work.
It is very possible that this will not work. Some ISPs firewall port 80 preventing their subscribers from hosting servers. Once you have your server directly connected to the internet you can test this (even if your dns is not working) by using the public IP address. As root, type ifconfig from the command prompt to get your public ip address. Then type the command tcpdump -i eth? port 80 from the root prompt. eth? needs to be the same interface that you saw had a public IP address from the ifconfig command. usually this is eth0 but it might be wire0 or something like that.
This command will show you all traffic coming on port 80 to your server.
From an iphone (or whatever second Internet connection you have) browse to the IP address that you got from your ifconfig command. If you see something on your server (and it is directly connected to your ISP) then your ISP is not firewalling you.
If you can get to your server, when it is directly connected to the Internet, either by IP address or by DynDNS address, then your ISP is OK and it is time to debug your firewall.
Two things need to work for your firewall to be configured NAT, where the public address that your router gets from your ISP is converted into your private network and a firewall rule which permits that traffic. If you get this far, then you know your firewall is the problem and then it is just a matter of getting its configuration correct. There are far to many home routers to document here, but you usually can find how-to instructions for your router for this task from the manufacturers website (usually it is part of the manual)
If you follow these instructions exactly you will get your system working. Make comments on the process and I will be happy to modify this to make it clearer.
HTH,
-FT
You should make sure your xampp is not listening to only the localhost.
to do so edit your apache configuration file and check and search for Listen directive
you should be able to know also by analysing the output of netstat -a.
After that make sure your router is forwarding properly, using tcpdump would help.
drop me a comment if you need more help.
Cheers

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