I have two servers, in different locations, running the same site (the second one, i think, would be called a "mirror"). I prefer the first one, but it has not-so-good uptime. I would like to create a website (in Javascript, HTML, Silverlight, or ASP.NET C# if possible) that checks if website #1 is up, and (if it is up) send the user there. If it's not up, it should forward the user to server #2. How can I check if the server is up (like http://isup.me/) and how can i forward the user there? Thanks!
There are many DNS providers that will do this for you automatically. The feature is called "Failover DNS" and it works like this:
for your domain e.g. example.com, you'd set an A record for the IP of server #1 (say it's ip is 123.123.123.123)
example.com A 123.123.123.123 TTL: 300s
www.example.com would be a CNAME to example.com
Then you would add server 2's IP address to the failover list for example.com. Then the provider will check server #1 every few minutes to see if it's up. Most providers allow you to configure how often and what to check to determine that it is indeed up.
If server #1 is down, the provider will start serving Server #2's ip address, so all traffic will be directed there.
You can read more about it here: http://www.dnsmadeeasy.com/enterprisedns/dnsfailover.html
Another provider that supports this is zerigo.com
If you are working for a company and scaliablity is a concern in future , please use some loadbalancer which automatically does it for you.
there are various options with loadbalancer to load the balance and route the traffic.
If you're using IIS 7, take a look at this article about Load Balancing.
http://learn.iis.net/page.aspx/486/http-load-balancing-using-application-request-routing/
Related
In the past, the domain was hired and used on a physical server (which still exists today)
And now I need this domain to stop directing the old physical server and start redirecting to the new one (which will also be physical)
Old Server : Linux Apache
New Server : Windows (IIS?, Apache?, WAMP? is still being decided)
Can someone give me a tip? I'm in the dark here
The first thing you should do is find the nameserver addresses available on your new hosting account.
The quickest way to find your new hosting account's nameservers is to look at the information in the email your hosting service sent you the first time you purchased hosting, or from the documentation provided by your hosting service's website. If you're still confused about where to get one, contact your hosting provider and ask them for a “DNS server” or “name server” for your domain.
Nameservers are usually in the form of ns1.companyname.com, ns2.companyname.com, etc., where companyname.com is usually the name/brand of your hosting service.
Your hosting service will generally provide 2 or more nameservers that you can use. Write down all the nameservers. It would be even better if you save the email/web page that contains the nameserver info so that later you can copy and paste it directly. Later in the next step, you must enter this nameserver information into the control panel where you purchased the domain (registrar), exactly as stated.
After you get the nameserver information, go to the domain control panel at your registrar. Don't forget, this means you're logging into the system where you bought the domain and going to where the domain management section is.
Once you find the appropriate page to change your nameservers, you will usually see a form that will allow you to enter Nameserver #1 (or “Primary Name Server”), Nameserver #2 (or “Secondary Name Server”), and maybe a few others (such as the 3rd and 4th nameservers). The terms may not always be the same, but the basic meaning will still be your first nameserver, 2nd and so on.
Fill in your nameservers, usually starting with ns1, into the Nameserver #1 field. After that type your 2nd name server, usually the name starts with ns2, to Nameserver #2, and so on. A domain name has at least 2 name servers associated with it. Some web hosting services provide more than 2, some only 2.
After the nameservers are installed with details, done. You only need to wait a moment until your website can be accessed using your domain name. Usually, it only takes a few hours for the machine to work properly.
You need to log into your Registrar account and update your DNS to point the domain to the public IP address of the new server.
This is normally a fairly easy and quick change. As an example, you can check out how to make DNS updates on GoDaddy here.
Depending on which new server you chose and the server provider, there may be additional steps involved in order for the new server to receive external traffic. Additional steps may include, but not limited to, updating a firewall and configuring the server settings.
I have a domain name registered at ovh.com, let's say it's called domain.com.
This domain is pointing on my router's public IP, then I redirect the https port 443 of my router to my server port 443. So when we go to domain.com it redirects to my server:443.
To be more accurate, domain.com just redirect to my router's public IP. So for example if I use a graphic database manager, I can tell him that the server address is domain.com:[SGBD port] and It will works.
But all my applications are running on this same server. And to add a little more security, I am not using the usual port for all protocols. So let's say my port are the following :
git : 50000
SGBD : 55000
cloud : 60000
website 65000
and some others, for example some TCP ports between 40000 and 50000.
My git and my cloud have a graphical manager I can access by typing domain.com:50000 or domain.com:60000 in my web browser from everywhere. I use the same URL on all my software. domain.com:50000 for my git client, domain.com:55000 for my database client and so on.
This way is working perfectly but there are 2 problems annoying me :
The first one is that I have to tell the port number to everyone who's susceptible to use my applications. But like I said I am not using usual port number for a little more security so I don't want to share these numbers with everyone.
The second problem is more important :
When I am somewhere, for example at work, it's possible that the firewall is blocking the port numbers I am using. So my personal git isn't accessible, same for my cloud etc.
To solve these problem in one move I wanted to add subdomain on my domain and redirect these subdomain to my differents ports. For example :
website : domain.com:65000
git.domain.com ==> domain.com:50000
SGBD.domain.com ==> domain.com:55000
cloud.domain.com ==> domain.com:60000
So in my mind, with this solution I can type git.domain.com in my browser to initiate the communication by https (the https port is almost never blocked), then redirect it to my router's port 50000 from OVH then my router redirect it to the git port of my server.
But obviously this would be to good to be truth.
When creating a subdomain (at least on OVH ?) we can't specify a port. So I can't set git.domain.com is redirecting to myRouterIp:50000 but just to myRouterIp. So with a web browser, typing git.domain.com will redirect to myRouterIp:443, which is already taken by my website.
So i'm a little confused. Do I have to buy one router with a different public IP per application then making all differents subdomain pointing on a different router ? I almost sure it's a bit ridiculous. How do you think I can solve it ?
As you correctly noticed, in your DNS console you can't specify port; the reason is that DNS does not care about ports, its only purpose is to resolve hostnames to IP addresses.
Another thing important for your problem is that most (non http) application clients will, even if they use friendly hostname, resolve that name to IP address before initiating the connection to your router/server, and then use that IP address for communicating to router/server. That means that when request reaches a port on your router/server, there will be no way for router/server to determine which hostname was initially used.
The rare exception to this is HTTP, where the browser is always sending the requested hostname in Host HTTP header. That means that you can run multiple different websites on one IP address on the same port (that is how shared web hosting works, for example). Setting this up should be pretty straightforward, but is probably out of scope on SO, try SF or SU.
For other (non HTTP services), the only solution is to run them on different ports (which you already do), or to have multiple public IP addresses (which might be difficult to get from your ISP). Also, running non-http services on some random non-default ports (and telling that port number to your users) might be (very sightly) more secure than running them on their respective default ports.
Depending on your use case, one other possible solution would be to have your users connect to your local network using secure VPN, and after that they could have access to your services (which would run on different private IP addresses and any port you like).
We have created self-hosted services using OWIN. They are working fine inside the server and we can request and retrieve information using the http://localhost. We use a different port for each service so that we can go and get certain information from http://localhost:8001, other from http://localhost:8015 and so on.
Now, we need to expose the results of one of those self-hosted services to access to it through internet. We'd like to provide a custom address such http://ourpublicinfo.mydomain.com:8001 or using the server ip such http://209.111.145.73:8001.
Is that possible?
How can we implement it?
Our server OS is Windows Server 2012 R2
OWIN Self-Hosted apps can run on a Windows Service, as a Console process and, with if desired, as part of a more robust Host like IIS.
Since you mention your app is running as a service you're probably missing all the GUI goodies IIS provides. In reality however, IIS works on top of http.sys, just as HttpListener does (which is probably what you're using to self-host your app) 1. You just need to do some manual set up yourself:
First of all, you need to make a URL reservation in order to publish on a nonstandard port.
Why would you do that? Quite simply because you're not running under localhost alone anymore on your very own local machine, where you probably are an admin and/or have special privileges/powers.
Since this is a server, and the user used for running the Service might not be an admin (most probably), then you need to give permission to that user to use that URL... and here is where URL reservations come into scene.
You pretty much have to options:
open up the URL to be used by any user:
netsh http add urlacl url=http://209.111.145.73:8001/ user="everyone" listen=yes
or open up the URL to be used by the user(s) running the service, e.g.: NETWORK SERVICE:
netsh http add urlacl url=http://209.111.145.73:8001/ user="NETWORK SERVICE" listen=yes
There is a way to make the reservation for several users too, using sddl, user groups, etc... but I'll not get into it (you can look that up).
Second of all, you need to open up a hall through your firewall (if you don't have one on this day and age, I pity you!)
There are plenty of tutorials on this. You can use a GUI, netsh.exe and what not.
Pretty much all you need to do is make sure you allow incoming connections through that port and that should do the trick.
To make sure the hall is open through and through you can use a tool like http://www.yougetsignal.com/tools/open-ports/ and insert 209.111.145.73 in the Remote Address and 8001 in the Port Number.
If for some reason it shows that the port is closed, even after creating an incoming rule in your firewall for it, then you probably have one or more firewalls in between your server and the outside world.
With those to elements in place you should be able to access your Self-Hosted Service from the outside.
As for accessing your service through an address like http://ourpublicinfo.mydomain.com:8001, you'll need to create a DNS entry somewhere, most likely on your Domain Registrar for mydomain.com, where you could create an A Record for your ourpublicinfo subdomain pointing to 209.111.145.73.
From this point on, you should be able to access your service through direct IP and Port or through the afore mentioned URL.
Best of luck!
Note:
If your service will be access from other domains, you might need to make sure you have CORS (Cross Origen Resourece Sharing) well defined and working on your service too ;)
Im just wondering, can 2 or more different external hostname/DNS redirect to multiple local servers but same port?
Let's see, I have 2 DNS internet domain for an example, myserver1.com and myserver2.com, and both I have same A record to my forwarded server IP (e.g: 102.123.123.123). Under my server which only has 102.123.123.123 IP address has 2 application servers but instead of trying to make they work, I use different port for each server applications for an example, serverApp1 listening to 0.0.0.0:2010, serverApp2 listening to 0.0.0.0:2020
My point is, is there any way or how to forward my myserver1.com:2000 to serverApp1 (port 2010), and myserver2.com:2000 to serverApp2 (port 2020) but both myserver1.com and myserver2.com has a same A record?
Im quite sure either it is in iptables or /etc/hosts or BIND issues, but guide me if I missed something. And by the way, the servers and DNS records are accessible from the internet which is the firewalls are configured properly. Thanks.
I don't have much experience in that, but I think you will need a third server/firewall/proxy listening for the incoming host and route it accordingly.
Again, I don't have much experience in that, so I'm not sure if the firewall is able to do that.
I think you can use redirection servers like apache.
In my application we want to access lot of intranet servers from internet. So what we did, we configured a apache with all the mappings in httpd.
So when ever a request to apache comes, it will be redirected appropriately.
For example - I have two servers or hostname in intranet : 1) abc.com:7300/context1
2) xyz.com:8900/context2
We configured a apache with host name abcxyz.com:9000. When a request like
abcxyz.com:9000/context1 comes it will be redirected to abc.com:7300/context1 and when a request like abcxyz.com:9000/context2 comes it will be redirected to xyz.com:8900/context2.
In your case since the requests are going through the single server (102.123.123.123), you can use redirection.
Hope it helps.
I'm implementing the PASV mode in a FTP server, and I send to the client the IP address and port of the data end point. This is stupid because the IP is actually where the client is already connecting, so there ire two options:
How could I get the public IP
address from a given instance? Not
the VIP, but the public one.
How could I get the original target
IP address that the user used from
a Socket object? Considering routers and load balancers in the middle :P
An answer to any of this questions would do, although there is another way that could work... may I get the public IP address doing a DNS look up of myapp.cloudapp.net?
A fourth option would be use the Azure Management API library... but, too much trouble :P.
Cheers.
Not sure if you ever figured this out, but here's my take on it. The individual role instances are all behind the Windows Azure load balancer and have no idea what the original, outward-facing IP address is. Also, there's no Management API call that returns IP address - Get Deployment returns the URL but not the IP address. I think the only option is going to be a dns lookup.
Having said that: I don't think you can host a passive ftp server in your role instance (at least not elegantly). You may open up to 25 input endpoints on your role (up from 5 - see my recent blog post about this update), but there's manual work involved in the configuration. I don't know if your ftp application lets you limit your port range to such a small number of ports. Also:
You'd have to define each port as its own input endpoint (this is the manual labor part I mentioned) - input endpoints don't allow a port range to be specified, unlike the internal endpoints.
You'd have to specify the port number that's used internally, and the port numbers would need to be sequential
One last thing on ftp: you should be able to host an sftp server with no trouble, since all traffic comes through one port.
The hack that I'm contemplating right now is to retrieve http://www.icanhazip.com/. It isn't elegant and is subject to the availability of that service, but it gets the job done. A better solution would be appreciated!