The Presence of the Running Machine on the Internet

Everything has a start, and has an end.

Deploying a server over the Internet is different from setting up a local server without being revealed to outside people. For a server to be unknown on the Internet by fully-qualified hostname, it requires some registration processes. Furthermore, since the server is known to the public, some security measures should have been taken to avoid the abuse of the server.

This package includes basic elements for network operation, for example, DNS, FTP, firewall, backup storage server, VPN (Virtual Private Network) and Email .

We start from the introduction on Domain name registration with the following diagram:

1. Purchase domain name from the “vendor for domain name registration”

The “Domain Name Registration Vendor” usually will provide a Web interface for you to query your desired domain name. You may find some of the domain names you like have been acquired by other people. It is necessary for you need to find a domain name that is not being occupied. And then make the purchase of the domain name from the “Domain Name Registration Vendor” to complete this step.

2. Purchase Internet bandwidth and obtain “static” IP addresses from your local ISP (internet service provider).

Usually, the ISP will give you a set of IP addresses that may include a list of public IP addresses, the netmask, and the default Gateway. This IP information will be used when you install the software and configure your server. You shall keep the information in a safe place once you obtain that from your ISP.

3. Find a legitimate “DNS host provider”

It is to host your domain name (which you get from step 2) and the associated static IP address (which you get from step 3) record so that everybody on Internet can use your domain name to reach your server. Usually, the “DNS host provider” will provide a Web interface to allow you to input your domain name and the mapped IP address record into their hosted server. This step is completed after you have entered the data into the web page.

4. Update the record at the “Domain Name Registration Vendor” server with the IP addresses of the “DNS host provider”.

At this step, you need to access the website provided by “Domain Name Registration Vendor”. If you do not know the DNS server’s IP addresses of your “DNS host provider”, you can do as follows at your Windows command prompt (the command prompt is reached through Start > Run > cmd), issue the command

　　C:\>nslookup DNS-server- name-from-your-provider

The system will respond with the IP address of your “DNS host provider”. Usually, you need to find two IP addresses of the two DNS servers provided by “DNS host provider” (one is called primary DNS host server, the other is secondary DNS host server). The two IP addresses will be entered into the record in the place of “Domain Name Registration Vendor”. We suggest using primary DNS server and secondary server from different places. The Azblink server package also provides DNS server. But to allow people all over the world can query your domain, you should have your domain name placed in different DNS servers to alleviate the load.

5. Wait until it is in effect.

In general, it needs 24 hours to 72 hours to have your domain name record of the server populated across the world so that people can use domain name to access your server.
Those are the general steps as long as you want to have your own private server(s) on Internet.

Basic Web Setting

After the system installation be finished, take the CD out, reboot the machine, and then start the basic network setting for the system.

There are two modes to configure the host, one is console mode on the local host, and the other is Web interface mode on Client. You can choose the one you like or just by the network environment of that time.

Console Mode --- configure on local host

A. Input account and password to login into console configuration interface.

　login：reset
　Password：root123

B. You will see 7 options after login in

　1. IP Address：192.168.19.185
　2. Netmask：255.255.255.0
　3. Default Gateway：192.168.19.1
　4. Save and Reboot
　5. Reset to CD setting (DHCP) and Reboot
　6. View Current Active Values
　7. Exit without Saveing Changes

C. Is there any fixed ip ready for configuration?

　 Yes, type fixed IP address, Netmask and Default Gateway into option 1.2.3. severally. You can use up
　　and down arrow to choose the option who needs edit, and then press enter to configure. After option 1.2.3
　　be correctly configured, you can use option 4 to save these changes and reboot the machine. (If you have
　　no idea about the Netmask and Default Gateway, you can just refer to the Completion List provided by your
　　ISP.)

　 No, if there is a DHCP server providing the IP assignment services in your network, you can just use option6
　　to check the IP address assigned by the system. After checking eth0, please write down the IP address, and
　　remember to use option 7 to quit the Console interface.

D. By the IP address you set or the one obtained from DHCP, you can view the configuration page of the
　　 system host via Web browser on remote Client.

※ DHCP server exists in your network, but if you find eth0 shown as IP 1.2.3.4 when you check current system value, please check if your network cables plug into wrong place (eh0 and eth1 may been exchanged), or if there are some problems on other equipments. (Refer to Q&A in the manual)


Web interface Mode --- configure at sub-network

A. Is the host, which you installed system on, connected by other hosts?

　 Yes, please confirm the host is the only DHCP sever (that is to say the network should not have other
　　DHCP servers, e.g. IP distributor), and then start from C.

　 No, please complete basic network configuration according to B’s instruction.

B. A network cable makes host’s eth1 port and the Hub connected. And use another cable to connect to
　　Hub, let the other end of this cable link to a common Client computer.

C. Choose one Client computer from the sub-network which connected to the system host.

D. Open command prompt on the Client (suppose it’s a Windows machine), type “ipconfig” and then press
　“Enter” button, check whether the Default Gateway is 172.16.9.1 or not?

　 Yes, just close the command prompt, enter into next step.

　 No, type “ipconfig/release” to release the old IP in your computer, and then type “ipconfig/renew” to get
　　new assigned IP.
　　(If you are still unable to obtain new IP, please check if the network has other DHCP sever or not, or maybe
　　TCP/IP of this Client does not use the mode of “Obtain an IP Address Automatically”.)

E. Open your Browser, and type http://172.16.9.1 at the address bar to link. When you visit the page at the
　　first time, you will see 4 items;

　　Host Name：Please set Host Name for this host.
　　Admin Password：Default password is admin123.
　　New Admin Password：Please set new password.
　　Confirm Password：Please confirm your new password.

F. After you enter into system page, go to System>>Network, choose Internet or PPPoE depending on the
　situation.

　 Choose Internet. At the Internet Interface, mostly, you should set the values for IP address / Netmask /
　　Default Gateway and then submit, restart your machine and you will find it already connected to Internet.

　 Choose PPPoE. If you use PPPoE, remember to check the checkbox of “Turn on PPPoE”. Fill in the account
　　and password provided by ISP and submit, reboot your computer, then you can connect to the network.
　　(Please refer to the sections of Configuration and Q&A in Quick Installation Guide if you have any questions.)

Basic Concept

Before we start the introduction of the functions provided by the firewall, it is better to review some concept about data networking in a very simple way. It is known that the data being transmitted over the data network needs to follow “specific” data formats. Then, after extracting the data received according to a certain format, the other party would do the associated actions correspondingly. This is known as “network protocol”.  Different network protocols have been applied to different occasions for different purposes.

This can be explained with an example. Your bag can be used to carry something from one place to another. You put something into a bag, and put this bag into a car, and this car will carry a lot of items to a very far place. “Bag” and “Car”, in this example, are used to carry things. But we know that they have different conveniences in different occasions – you would not drive your car from your kitchen to your living room on the hallway of your house because it is not “convenient”. But to travel a long distance with many articles, you would use the car.

The diagram above indicates some of the network protocol hierarchy in some applications. TCP ( Transmission Control Protocol ) and UDP are based on IP. In other words, the two protocols are encapsulated by IP packets. And IP packets might be placed into Ethernet payload or else as indicated in the diagrams above. Further, there might be some other protocols that are based on TCP or UDP. For example, http is usually implemented on TCP. To get what is inside “http”, it is needed to “open” the IP packet first. 

From the header of IP packets, there is a field for “IP address”. Sometimes, the higher layer of protocols might also put the information of IP address into their data payload to indicate where the data originally comes from.  It shall be noticed that sometimes the IP address from the IP header might be different from what it is described in higher layer of protocols ( like http ) because of some “manipulation” during transmission. And this is what we are going to introduce.

The term “Border Control” here in this software mostly handle the manipulation on the network packets on TCP/UDP/IP layers.  For TCP or UDP, it is only up to the traffic associated with the logic port(s) should be accept, redirected, dropped, or forwarded. For some other functionalities regarding to the processing logic of higher layers of protocols, they have been handled in some other places. 

The basic functionalities of the firewall described here are: it blocks the traffic “initiated” from the hosts outside the firewall to enter the network it protects. The sentence above needs to be clarified a little: if all the traffic from outside hosts is blocked, how do the people inside the firewall view the Web Pages on the hosts outside the firewall?

For the outgoing traffic from the hosts inside the firewall to the hosts outside the firewall, the firewall will not block this kind of traffic. Furthermore, those “Response” or “Reply” packets from those outside hosts will not be blocked in response to those original requests from the hosts inside the firewall. However, how does the firewall know what kind of packets are “Response” ?  The details are out of the scope of this document. It is roughly determined by some characteristics of the network protocols, like sequence number, sender, or receiver, or the previous states kept in the firewall.

Another function of the firewall is: it is with NAT ( Network Address Translation or Network Port Address Translation ). Basically, it allows the hosts inside the firewall sharing one “Public Signature” ( public IP address ) by hiding their private IP addresses being used inside firewall.



For those functions described above, you do not have to set the rules in the web interface of the firewall to perform the desired functions above – they are set already. And those rules will not be seen via Web interface; they are considered to exist from the very beginning when you try to add the other rules into the firewall. The following sections will introduce how we add other rules into the firewall for other functionalities.