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.)

The Usage of DMZ ( De-military Zone ) of Border Control

 When only 2 Ethernet interfaces are present ( known as “eth0” and “eth1” ), we partition the whole network into 3 regions by labeling them as “loc”, “fw”, and “net”; the region “net” stands for the network connecting to the interface “eth0”, the region “loc” stands for the network connecting to the region “eth1”, and “fw” stands for the firewall machine itself.

By default, we allow any stations in “loc” to access the region “net” freely. From the region “net” to access the servers located in “loc”, Port Forwarding (DNAT) needs to be applied by adding the corresponding rules.

After the CD release at the date around September 2007 (internal code name for that CD release is “ted83.iso” ), the firewall will automatically be configured for the usage of DMZ when 3rd Ethernet interface “eth2” is present. For the previous releases, it was designed for the usage of two Ethernet interfaces; if the 3rd Ethernet interface “eth2” was present, the region connecting to “eth2” also belonged to “loc”. But starting from the release “ted83.iso”, the region connecting to “eth2” is labled as “dmz”.

In previous releases, if “eth2” is present, it still belongs to the region “loc” with different subnet address space as the following diagram indicated. It is necessary to use the notation “loc:172.16.9.0/24” or “loc:172.16.10.0/24” to apply additional rules on a specific area in “loc” region. So, it can also achieve the similar configuration for DMZ functionalities in this way.



In the release of “ted83.iso”,  “dmz” will show up when 3rd Ethernet interface “eth2” is present:

Some pre-defined rules already exist for “dmz” by default; those rules do not have to be added when you use the firewall; those predefined rules are not shown on the Web UI so that you should always keep in mind about those “pre-defined” rules:  it is forbidden for those stations inside the region “dmz” to access the region “loc”; the firewall itself “fw” can not be accessed from “dmz” unless some additional rules are added into firewall for that action.   

In our system, “dmz” is not completely “de-military” by default; you have to use “DNAT” action in the “Advanced menu” to forward the traffic into specific host in DMZ.

For example, if we want to forward the traffic associated with IP address “1.2.3.4” TCP port 25 to a host located in DMZ with private IP address 172.16.11.12,

If you only have one IP address 1.2.3.4 binding on “eth0”, you can just use

Action: DNAT
Source: net
Destination: dmz:172.16.11.12
Protocol: TCP
Destination Port: 25

If “IP Aliasing” is used by binding multiple IP addresses on “eth0”, it is necessary to specify “Original Destination IP” explicitly:

Action: DNAT
Source: net
Destination: dmz:172.16.11.12
Protocol: TCP
Destination Port: 25
Source Port: - 
Original Destination IP: 1.2.3.4

The hosts in “loc” can use “172.16.11.12” to access that machine in “dmz” directly. If you prefer the traffic from “loc” with destination IP 1.2.3.4 and destination port TCP 25 to be forwarded to 172.16.11.12, you should add the following rule

Action: DNAT
Source: loc
Destination: dmz:172.16.11.12
Protocol: TCP
Destination Port: 25
Source Port: - 
Original Destination IP: 1.2.3.4

And let’s take a look at more examples. If you want to deploy a VoIP server into “dmz”, what is the necessary step to do?  Assume “1.2.3.5” is the public IP address for this VoIP server known in the public internet and its private IP address is 172.16.11.33.




If the VoIP server is using IAX protocol, it is sufficient to forward UDP 4569 to the private address of that VoIP server:

Action: DNAT
Source: net
Destination: dmz:172.16.11.33
Protocol: UDP
Destination Port: 4569
Source Port: - 
Original Destination IP: 1.2.3.5

If the VoIP server is using SIP ( Session Initialization Protocol ), then the situation is a little bit more complicated because it usually comes with stream using RTP ( Real-time Transport Protocol ). If it is using TCP/UDP 5060 for SIP and UDP ports 10000 to 20000 for RTP media stream, we should set

Action: DNAT
Source: net
Destination: dmz:172.16.11.33
Protocol: TCP
Destination Port: 5060
Source Port: - 
Original Destination IP: 1.2.3.5

Action: DNAT
Source: net
Destination: dmz:172.16.11.33
Protocol: UDP
Destination Port: 5060
Source Port: - 
Original Destination IP: 1.2.3.5

For the range of RTP ports, we can use

Action: DNAT
Source: net
Destination: dmz:172.16.11.33
Protocol: UDP
Destination Port: 10000:20000
Source Port: - 
Original Destination IP: 1.2.3.5

Our philosophy is: you only need to open necessary ports and forward the traffic to the host – no other port should be opened for access to avoid the attack from the crackers.

But there is a chance that the communication scheme is quite complicated that it does not use any fixed TCP or UDP ports so that you have no way to use traditional rules. In this case, you might just forward “all the traffic” associated with a specific IP address to that host. For example,

Action: DNAT
Source: net
Destination: dmz:172.16.11.33
Protocol: TCP
Destination Port: -
Source Port: -
Original Destination IP: 1.2.3.5

The rule above just forwards all the TCP traffic to 172.16.11.33. You can forward all UDP traffic with similar scheme. In general, you should not do this because it just puts the firewall into no use by allowing any traffic to reach that host.