atcomsystems.ca/forum Forums VOIP Phones & IP PBX Networking static ip issue

Sentrex - I love to teach so here is what is going on with your setup on a high level now that it is working...

Your network has a network address (aka a wire address) of 192.168.2.0 The subnet mask of 255.255.255.0 determines this. Each digit of an IP address is called an Octet and is based on a 8 bit number. It can have a value of between 0 and 255. The subnet mask determines what part of an address is the network and what part is the host (PCs, printers, servers, router etc...) For now, since you are learning, the 255 masked the entire number so the network above is 192.168.2.XXX

The last octet is reserved for hosts. As explained above, it can be any value between 0 and 255. This would lead you to think you can have 256 devices right? Wrong! 0 is reserved as the network address (think of this as the network ID) and 255 is a special address that sends information to all devices on a network (1-254). So we now have 1-254 available to assign to devices meaning we can have 254 devices on this LAN.

Every device must be assigned an IP address of 192.168.2.(something between 1 and 254) in order to communicate with other devices. The last digit must be unique. You cannot have 2 devices with 192.168.2.200 or you have created an IP address conflict. What will likely happen is one of the devices NIC cards will shut down until you fix this. If you assign a workstation the same address as your router though, you might kill your internet until you find it.

Your devices connect to a LAN switch. The switch has a table that maps the MAC address (a unique 12 digit address assigned to every device out there) with the IP address assigned by you or the DHCP server.

DHCP vs. static - For workstations, DHCP makes management easier. Your router can be configured to assign addresses to stations automatically so you don't run into the adventure you had today. That being said, sometimes a static address is needed for an email server or surveillance and (definitely) the router.

When you assign a static address you need 4 components. An IP address and Subnet mask as explained above. The default gateway will be the address you router has (192.168.2.1). Lastly you will need a DNS server assigned (also 192.168.2.1) As you saw, once these were configured it worked.

So here is what is going on. Internal vs. outside...

When I ping my DVR (192.168.2.199) from my PC (.198) the PC sends out a special packet that will be replied to from the other side if it is received. The switch knows where .199 is and sends the packet to the DVR. The DVR responds with a reply back to .198 which the switch, again, knows how to get to.

If I ping 8.8.8.8 the computer already knows this is in a different network so it will send the request to the router (.1) to find it. If no default gateway is configured (or incorrectly configured) the process will fail.

Your router is a device that connects 2 or more networks together (in this case your 192.168.2.0 network and the Internet)

If it can get to the router and the router can find 8.8.8.8 on the internet you will get a reply back.

Now we are good with IP addresses. So I ping google.com and get a result that the hostname could not resolve. There are special servers on the internet that maintain databases of which IP address is associated with which human friendly name such as google.com Google.com might be IP 74.68.7.190 but no one is going to remember that so we have DNS servers out there to resolve names to IP addresses. You router by itself is not a DNS server but it did a DHCP to your service provider to get an IP address, subnet mask, default gateway and DNS servers (sound familiar now?) from the SP network. If you google search "What is my IP?" you will see the external IP address to your network. Your firewall will (hopefully) keep out all traffic except for that you allow in.

This is a good base to build on - It does get more interesting when you learn about more complex subnetting, routing, and other concepts but as far as simple LAN setups you have really accomplished a lot today. Before you know it neighbors, family, and friends will consider you there go to guy. ~ Mike

In closing from a cmd line type tracert google.com and you will see the path the packet takes. Basically it is router to router to router until it gets to google. There are webpages that will even graphically show the path on a world map.

its a BELL sagemcom fast 4350 home hub 1000

wow thanks michael that puts it in a way that i now understand

Just want to tack on one quick addition to Michael Meyer's excellent lowdown.

For local area networks (versus WAN/Wide Area Networks), there are three ranges of IP addresses normally used for internally assigned IP addresses.

10.X.X.X
192.X.X.X
172.X.X.X (this is the least commonly used one)

These addresses aren't used outside of Local Area Networks, because this would cause a conflict, as your router wouldn't be able to distinguish between local traffic and requests for content outside your network.

Here's an example of a traceroute to Google.com, like Mike mentioned:


--------------------------------------------------------





Hope that helps.

Scott

You guy's have made me so happy,my network works my ip office with ip sets works i can go on the internet and i understand now the basics,
I hope i can help you guy's out in the future
Alain

Just to clarify, the RFC 1918 private IP ranges go like this:
10.0.0.0-10.255.255.255
172.16.0.0-172.31.255.255
192.168.0.0-192.168.255.255

https://en.wikipedia.org/wiki/Private_network