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Configure IIS for internal c# web application

I have a number of C# web applications that I have deployed to our in house web server so they can be available only to our internal users.
The webserver is running IIS 8.5 and I have set up a couple of sites in this that point at the applications, this is working fine except that the url you have to use to navigate to the applications is in the following format serverName:portNumber.
I would like to change this so the urls are more user friendly and they dont have to remember the server name and the port number.
I am an IIS noob so I don't know what to look into/try so any explanation using words of one syllable would be greatly appreciated!
I have seen that this might involve something to do with bindings (?) so I have included my current binding settings for my sites below.
Site1
Name: MySite1
Type: http
Host name: null
Port: 80
IP Address: *
Binding Information: null
Desired URL: www.mysite1.com or something equivalent
Site2
Name: MySite2
Type: http
Host name: null
Port: 81
IP Address: *
Binding Information: null
Desired URL: www.mysite2.com or something equivalent
Thanks in advance

In IIS you can right click on each website and go to Edit Bindings and you will be able to configure IP addresses and ports in there. If you leave the IP address as * (or "All Unassigned" as IIS calls it) and you want to have multiple sites with the same port number (80), then you need to specify the host name for each site. www.mysite1.com for the first site and www.mysite2.com for the second site as in your example. Of course you'll have to make sure those host names are in DNS so that your users will be able to connect to the server when they type in the URL.

Try changing bindings from C:\Windows\System32\drivers\etc
There will be a line '127.0.0.1 localhost' which you can uncomment and add your ip's here.
eg : ip : port staging.yoursite.com

Hostname with Special Caracteres

In my WCF service, I need to publish it in the Bonjour service. The reason for this is to make the customers that consume my service know which computer it is running.
This works well.
But when I have machines with special characters in HostName, customers of this service can not eat because an error occurs in time to resolve the url.
Example: "http://máchine:8888/service.svc"
One solution would be to use thought to solve here the IP of the machine in place of the hostname. But when the computer works only with IPv6, I can not publish the service because the following error occurs: "Inalid URI: Invalid port specified."
How can I solve this problem without changing the HostName?

In my experience, when mapping zeroconf services to URLs, it's best to not rely on the service's host name. Resolve the service to an IP address (for example, with avahi, using avahi_service_resolver_new) and use the IP address in the URL. This avoids all sorts of problems with fancy hostnames and system resolvers that can't resolve zeroconf names (often the case on embedded systems).
If you got an error like "Inalid URI: Invalid port specified.", it sounds like you might simply have neglected to enclose the IP address in [square brackets]. The pseudocode for forming your URL should be:
if IP address contains ":"
url = "http://[" + ip address + "]:port/whatever"
else
url = "http://" + ip address + ":port/whatever"
There are two additional complications:
If you are using HTTPS, certificate matching will probably fail because the common name on the certificate won't match. It's not clear what to do about this in general because the very nature of an autodiscovered service usually means you can't meaningfully authenticate the server anyway. So you might be able to get away with just turning off certificate verification in your HTTP client.
You might not be able to use IPv6 link local address because there is a deficiency in the standard (RFC) for URL syntax that means it is not possible to attach a % character and an interface name to the address in the URL. Some HTTP clients allow the obvious extension to the standard to support scoped addresses, but others don't (for example, all of the major web browsers don't!).

Get external IP address of a website

I have seen many methods for easily retrieving the internal IP address of a machine or website. However, I can't seem to find a good way to retrieve the external IP address.
To clarify, if I provide a URL like bitbucket.org, I want to get the external IP address of bitbucket. Is there a web service out there that can easily do this?
EDIT: Suppose, for this case, that I am on the same network as bitbucket.org.
I am filling a database with information about all the websites our company manages. We want to keep track of the info and note periodic changes, with specific data. This program will be deployed on one of the local servers on the same network as the servers that the websites are running from. I believe the only good way of retrieving the external IP address for each site is to use an external web service.

You can use System.Net.Dns.GetHostEntry() to get IP address by the host name.

You could query an external public DNS server, e.g. Google's one at 8.8.8.8. From the command line
nslookup bitbucket.org 8.8.8.8
or in Linux dig bitbucket.org #8.8.8.8. There's a few C# libraries out there that will let you query a specific DNS server e.g. DnsNet built on top of this CodeProject article (found searching - I haven't tried it to recommend it). This does rely on Google continuing the service, though, but that seems safe.

You can use the ping utility. In windows, open up a command window by hitting the windows key + r and type
ping bitbucket.org

I think you can just use Dns.GetHostAddresses to get the IP Address. From the MSDN Documentation:
The GetHostAddresses method queries a DNS server for the IP addresses associated with a host name.
UPDATE:
If you are looking for a web service, try looking at whoisxmpapi.com. As you can see from this sample, they do provide the name server IP Address in their XML output. You can then use something like this to get the IP address directly from the name server!

If you are trying to get your "wan" ip instead of your local IP you could try something like this.
You could also add code like this inside a webservice and add it to the PC bitbucket is on (if it is really on your network and you can have access to install webservices).
Public Shared ReadOnly Property IpAddress() As String
Get
If String.IsNullOrWhiteSpace(_ipAddress) Then
Try
Dim webClient As New WebClient
Dim result As String = webClient.DownloadString("http://checkip.dyndns.org")
Dim fields = result.Split(" ")
_ipAddress = fields.Last
_ipAddress = _ipAddress.Replace("</body></html>", "")
Catch ex As Exception
_ipAddress = "errorFindingIp"
End Try
End If
Return _ipAddress
End Get
End Property

Re-writing the Hosts file does not update the next IP connection

We have a written a C# application that communicates with any one of a group of IP in the cloud.
Any one of which may not be working. We use the URL of the address as the IIS server is expecting a Host Header Name in order to route to the correct application interface.
So we set the Hosts file to point the URL at an IP.
We then send a command at the URL to get back the server time.
This tells us the connection is working.
If we don't get a response we assume the connection is dead. We then write a new IP from a list into the Hosts file and we try again.
This is where we hit a bug. The application doesn't seem to see the Hosts file has changed and uses the old (bad) IP.
There is no caching built into the application so we are assuming that Windows is caching for us.
We've tried to flush caches with:
ipconfig /flushdns
arp -d *
nbtstat -R
We still get the same problem.
Any thoughts on how to clear the cache?

If you can't address this at the server end (e.g. a load balancer, etc), then just use the IP address list in your code:
var req = HttpWebRequest.Create("http://" + IPAdd.ToString() + "/path_to_query_time");
((HttpWebRequest)req).Host = "yourhostheaderhere";
var resp = req.GetResponse();
//If things have gone wrong here, change IPAdd to the next IP address and start over.
Don't go messing with the users settings to try and solve a problem in your application that's of your own making.

Can't resolve DNS

I'm trying to consume a webmethod but it seems that my application can't resolve DNS. The problem surfaces when I configure my application with an url (e.g.: http://mywebservice.com/webservice/methods.asmx), but it does not when I access the same webmethod through the server's IP address.
The thing is that I need to access the webservice using the url and not the IP address due to an existing DHCP server policy.
Can anyone help me ?
Thanks in advance.
UPDATE: Checking out what moocha asked me to do, I found out that:
D:>nslookup server.com
Server: dnsserver.mycompany.com
Address: XXX.YYY.XXX.YYY
*** dnsserver.mycompany.com can't find server.com: Non-existent domain

Have you tried confirming the same DNS query works via nslookup from the same system on which your application runs?
I.e.,
C:\>nslookup
Default Server: whatever.dns.example.org
Address: 111.222.333.111
> set q=a
> mywebservice.com
Server: whatever.dns.example.org
Address: 111.222.333.111
Non-authoritative answer:
Name: mywebservice.com
Address: 208.254.26.139

Digging a little bit more I found that there is a proxy in between my PC and the server. Therefore, I'm oblied to log with a valid user in order to access the internet. The problem was that my application's server (where the IIS is running) was configured to run using anonymous access. All I had to do was to configure in the IIS an user that has permission to access the internet (through the proxy). Finally the problem is solved.
There was another option, I could use the logged user's credentials to grant access through the proxy; but that required that all users use the same log in information for the application and the intranet.