static and dynamic host configuration approaches? - networking

I'm currently revising for an exam and I'm stuck on a question which is:
"Explain the static and dynamic host configuration approaches."
I'm unsure if the answer is correct but what I've write is this:
static host configuration are hard-coded addresses that will only work on one specific network segment, which is intended for stationary computers
dynamic host configurations work best with portable computers like laptops that move between network segments.
that's my answer, could anyone help me to understand if this is correct or not?

You are correct about the difference. But there s a lot more than what you have stated.
DHC : Used to configure IP addresses automatically to the systems without any intervention of network administrator.
For Eg. When you register for a new internet connection, your ISP(network administrator, in this case) will provide you access to the DHCP server which ll allot you the IP address on the runtime.
To prevent the same IP address being assigned to two different computers
Also the main use is, ISP s will have a range of IP addresses with them. You ll be assigned any of their IPs dynamically by DHCP Server when your lease time expires for a particular IP that have been assigned earlier
SHC : Used to manually configure the IP addresses to systems.
When you knew how many systems are going to be present exactly inside the network
And when you want to uniquely identify a system in the ntwk using its IP address
For Eg. When you configure LAN in your house, between, say, around 4 computers. You will know exactly the number of systems in the group. So you don't have to allot a DHCP Server to allot the IP addresses for these 4 systems. YOu manually configure them
Hope that helps :)

Related

Local Area Network Configuration Question

Comcast installed a Juniper Universal Access Router ACX1100, I plugged our switch to the port that the technician told us that is in/out port. But nothing happened, after reading and asking I was told that I need a managed switch to be configured with the gateway IP and that IP is a /29. That's where I got lost. According to him there are 6 usable IP's.
example:
Gateway: 192.168.120.161/29
Usable Range: 192.168.120.162 - 192.168.120.167
One of my multiple questions is what hardware do I need to be able to connect my PC's?, I configured a managed switch, but when I connect my laptop to it I get Unidentified Network and No Internet Connection.
I have been reading and I think I need a VPN with DHCP server integrated.
If some one can help me I'll appreciate it.
/29 is the subnet mask, it can also be expressed as 255.255.255.248. Basically it defines which part of the IP is the network ID and which part of IP is the host ID.
I think in order to accurate assess your situation, we need to know exactly what kind of configuration you set on the managed switch you purchased, also which managed switch did you purchase?
Also currently on your laptop's NIC, what IP is assigned on there?
Either on your old unmanaged switch or on the managed switch, you can try assigning one of the addresses from the /29 block that the technician told you about statically. And the default-gateway with the addresses you posted in your question.

How can I programatically set the IP address of a hardware device that doesn't already have an IP set

We have developed a hardware device that doesn't have a screen. It uses TCP/IP to communicate with the network. Currently this is configured by DHCP.
However, we'd like a way to configure it's IP statically by some app I'll have to develop. I notice for some devices like printers there are custom apps that they use to set such information. But how do they talk to the device when the device hasn't been assigned an IP already?
Are they using RAW sockets and a custom protocol? or is there a simpler method. For example, I recall many years ago using a Linux device that somehow received it's initial IP by running an arping. But I don't understand how that sets the IP for other hosts on the network. Nevertheless it seemed to work. Could I mimick that?
e.g. arp -s 191.168.2.2 00-40-9d-22-23-60
So I've got an idea how it works, but I'd like to know what is the common method of setting IP to an embedded device that has no physical screen to configure this.
To be clear, this device does not use Linux.
The standard-conformant way of doing this goes (for IPv4, but IPv6 is similar) along the lines of:
Try to obtain an IP address via DHCP, skip step (2) if that worked. This should be the default.
If no DHCP server responded, use a unique link-local address (These are addresses from the block 169.254.0.0/16 reserved for this purpose. Some parts of the chosen address should be based on something unique to the device, like the MAC address, to make sure the device always chooses the same LL address. Or, to make it fully RFC-compliant: choose a truly random address from this range and probe it - Re-use it when possible) The chosen LL address should be checked against any other use in this network before usage with an arp request on that address (That's probably what you have read). If someone responds to that request, choose a different IP and retry.
Now that you have a temporary IP address, you can use one of the various IP-Multicast-based service discovery protocols to advertise your device to the network.

How does Network Address Translation affect computers on the network?

(I’m asking the question here because most of the other similar questions on StackExchange seem to be here — please let me know if there is a more appropriate community).
I have a number of computers on a network with a Linux Server running iptables, which is using Network Address Translation.
Not being an expert, I understand that the role of NAT is to take the internal 198 IP addresses, forward them to the external host under a common external IP address, and, when the response arrives, reverse the process.
If a number of internal machines make requests to the same external host, does this mean that host thinks they’re all coming from the same machine? What implications would that have for security or if the host wants to blacklist a machine?
"The router knows where packets belong because The router saves ... an address translation table. It remembers what inside-outside address translations it has made. As such, one inside address equals one outside address, and the out-on-the-internet destination is irrelevant. This, of course, ignores the firewall present in practically every NAT router, which tracks full connections:"
How NAT Port forwarding works

IP Comparison between 2 Locations

can one location have more than 1 IP address? I have 2 IP addresses and need to know if they originate from the same source. Thanks
You're missing clear definitions of "location" and "source" in your question but lets go with the assumption that you mean "physical machine" for both (as it's obvious that multiple machines will have different addresses and that a single machine can change its IP address over time).
In that case, the answer is yes. The operating system may bind as many IP addresses to a physical network port (and a single MAC -- the physical addressing used by Ethernet) as it wishes.
Binding multiple IP addresses was the standard way of doing "virtual web hosting" before HTTP/1.1 arrived with the "Host" header. The provider would use DNS to map different host names to different IPs on the same network (usually the same subnet as well) and then assign all of them to the same interface. The webserver would get address information from an incoming connection and based on the local IP address would know which virtual host was being accessed.
This led to a higher-than-typical use of public IP addresses but the practice is now gone with the proliferation of HTTP/1.1.
I'm not sure how Windows presents it, but Linux will present a physical interface with multiple IP addresses as multiple logical interfaces such as "eth0", "eth0:1", "eth0:2", etc. Each logical interface has a unique IP address even though they share the same physical interface.
This is hard to tell. Especially it is hard to tell if these IP addresses are from different times. Today I may have a different IP address than tomorrow.
Even they are from the same time, a load balancer im my internal equipment might send my packets over the fail-over line if the 1st one is overloaded or broken down.
One network adapter normally has only one IP address at once and a typical end user only has one network connection active, but even then the IP address can change. The user could switch from wireless to wired and back or a power outage might reset the ISP's DHCP server (assigning everyone a new IP address).
If you want to identify the user even if his IP address changes, you need to identify the user by his session id, stored in cookies. As two users can have the same IP address (a whole company could be behind a NAT), you should never rely on IP addresses for identification.

IP Changing Program

So, my work has several networks and small business locations all with an internet blocking server. The managers all rotate and want freedom from the server, AKA static IP addresses outside the range of DHCP.
my problem is that they all need access to each others network, so setting up an alternate configuration is not that useful. How would I create an application that will change my users IP Address so that it will match their static IP at the location they changed it too?
This is just their internal IP address on their local machine, and each location's network has a static ip waiting for them. Just have to change their IP Address.
Is there a batch file command that can help achieve this? if not maybe writing a script or going into a larger application?
Doing this on the machine itself will be difficult. It needs to be able to recognise each network, and what will it do when connecting to an unknown network like a home network or a hotspot?
I think it would be better to let the DHCP server hand out static addresses from outside the normal dynamic address pool. That way everything keeps working automatically while also giving static addresses to the machines.
I know this is not a real answer to your question, but I hope this gives you an alternative.

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