# Solved: LAN Ip keeps changing !



## redhatcode29 (Jul 3, 2014)

guys, i am using synergy to control my W8 from my Mavericks. However the LAN ip keeps changing....hw do i fix this. I a just a bit puzzled coz, i use to control both the W8 and Mavericks with a Windows XP, which never had the IP issue. Now that i have discarded the XP rig, i am having this problem wherein i have update the LAN ip from the mavericks to the W8....each and every time i log in ! 

Any ideas hw to overcome this ?


----------



## hackery (Jul 17, 2014)

People who run servers do so by setting a port forwarding rule in their router. Because their IP address is automatically assigned to the computer by the router each time you turn it on, it is possible for this IP address to change if you have more that 1 computer on your LAN. If this happens the port forwarding rule becomes invalid. Because of this your website and other services that require port forwarding will fail. To get it working again you have to change the port forwarding rule to the newly assigned DHCP address. Static LAN IP Addresses stop this from happening.

Mine looks like this:









My router has the "Starting IP Address" as the field we need to set. I set mine to 192.168.1.110 as the start of the DHCP Range. This allows the IP's 192.168.1.110 to 192.168.1.254 to have DHCP assigned PC's on it. We need the static range which is 192.168.1.100 to 192.168.1.109.

You need to set a suitable range for yours. I suggest you follow mine as much as possible, despite slight differences in the IP's.

When you have selected a range, save the settings on your router.

Next you need to set the IP address on the computer acting as a server.

1. Right click "My Network Places" on your desktop and click "Properties" (or double click "Network Connections" in Control Panel).
2. Now right click the network adaptor and click "Status". On the box that appears click the "Support" tab then click the "Details" button.








3. Copy down the details you see in the box, especially the DNS Servers.

4. Now click OK until you get back to the screen with the network adaptors on it.
5. Now right click the network adaptor and click "Properties". On the box that appears, click on the TCP/IP protocol, then click the "Properties" button.
6. Now enter the details you just copied down into the boxes and enter an IP address that is outside the DHCP range you specified. This will be the servers new permanent IP.









6. Now click "OK" on both boxes and the IP address should be changed.
7. Now check that your internet still works by browsing to a site you have not visited recently. This ensures the browser is not pulling the site up from the cache.

8. Now that the internet is working, you need to change your port forwarding settings to point to the new IP address of the server. Once you have done that and applied the settings, you have finished.

You should never have to change any of these settings again unless you hard reset your router, change the IP settings or reinstall Windows.

hackery


----------



## Headrush (Feb 9, 2005)

I don't know that specific router, but most decent ones allow you to set DHCP reservations also.

This will accomplish the same thing as using static IPs but you can leave you clients using the default DHCP setup.


----------



## redhatcode29 (Jul 3, 2014)

Hi hackery, 

Thank you so much for the lenghty explanation. Appreciate it. I ddnt know tjat there were this many settings to meddle with. 

However, due to my current situation, i am not even using a router! Mu rigs are connected to a very basic 8 port network switch. My net connection is via wifi. 

I guess i should have stated this in the initial post. However, it is going to take me a while to digest your explanation. I suck at network issues!

Thanks again.


----------



## redhatcode29 (Jul 3, 2014)

Hi headrush,

Thanks, will try to digest your explanation. Kinda confused right now...


----------



## Headrush (Feb 9, 2005)

What exactly is W8?
After Hackery's post I assumed it was some kind of router you were referring to.

Can you explain exactly what you mean by your net connection is by WiFi?
The Internet from your ISP is Wifi and then goes into your switch? (unless by chance you are sharing a neighbours)

Can you give us an idea of the IP your computer gets while connected? e.g. 192.169.xxx.xxx (We don't need to see all numbers, just first 2 parts)


----------



## redhatcode29 (Jul 3, 2014)

Hi, 
Ok .... W8 (Windows 8), which is in the LAN with my Mac Pro. 
- previously all my rigs were connected to a router, which was connected to a ISP' s modem 
- now, for certain reasons, I am not using the same ISP, thus I am not using any router, while for networking purposes, I have connected my rigs to a very basic 8 port network switch.
- for internet connection, I am using a portable modem, to which my rigs connect via wifi. 

- I am using Synergy (keyboard & mouse sharing software) to which I am using my Mac Pro as the server. 
- as such, the Windows 8, is run with the Mac Pro's keyboard and mouse. 
- thus, as the Ethernet ip add of the Mac Pro keeps changing, I am having difficulty to run the Windows 8.
- I checked the Mac Pro's network settings, (system preferences >network ) the LAN connection reads as (self assigned ip)
- I am not sure if this issue is caused because I am not using a router but rather a network switch for my local network.

- however, the issue of the changing ip is recent. 
- prior to this, I was using a windows xp as the main rig, whose keyboard and mouse was shared with both the windows 8 and the Mac Pro. 

- the significant change I made to my hard wares was the addition of a wifi adapter to my Mac Pro to which I had issues and had posted a thread in this forum. 
- I belief that in the process of installing the software for the wifi adapter in my Mac Pro, some settings could have been messed up! 

I will post my ip add once I get home. 

Thank you so much.


----------



## Headrush (Feb 9, 2005)

redhatcode29 said:


> Hi,
> have connected my rigs to a very basic 8 port network switch.
> - for internet connection, I am using a portable modem, to which my rigs connect via wifi.


Just to be perfectly clear, you are saying your rigs (computers) are connected to your modem by Wifi *and* also connected to each other via the switch?


----------



## redhatcode29 (Jul 3, 2014)

True...... Is there anything wrong with it ! Have I done smthg dumb ! 

But come to think of it.... Only the Mac Pro is connected to the wireless modem, most of the times, I dnt use the windows 8 for internet purposes, I connect the windows 8 to internet wirelessly only to update the antivirus and malware. 

Are u saying that I should not have a LAN and a wireless connection at the same time ....


----------



## Headrush (Feb 9, 2005)

Having both is fine but that helps understand things better.

By chance was the IP you were getting that was changing, start with 69.x.x.x?

Either way, with this setup, you need to set up all the machines on your LAN with static IPs.
OS X will be smart enough to use the right connection for LAN or Internet depending on the need.


----------



## redhatcode29 (Jul 3, 2014)

Headrush said:


> Having both is fine but that helps understand things better.
> 
> By chance was the IP you were getting that was changing, start with 69.x.x.x?
> 
> ...


My ethernet IP starts with169.254.X.X

When you say that i need to set all my machines to have a static IP, how do i do that...in my Mac Pro..


----------



## Headrush (Feb 9, 2005)

Sorry I meant 169.x.x.x

Go into System Preferences -> Network 
Pick Ethernet connection on left side, in Configure IPv4 using pulldown menu choose manually.

Your local machine will all start with 192.168.y.x
You can pick unique values for x on every machine on your LAN.
y is a unique number you choose, but every machine on your LAN will use the same value here.
For subnet mask use: 255.255.255.0

Since this interface is only used for machine on your LAN and not Internet, you shouldn't have to set router, DNS for that connection.


----------



## redhatcode29 (Jul 3, 2014)

Thanks Headrush, I've set my Mac Pro to stay put with an ip add without changing upon every boot.


----------



## hackery (Jul 17, 2014)

redhatcode29 said:


> Hi hackery,
> 
> Thank you so much for the lenghty explanation. Appreciate it. I ddnt know tjat there were this many settings to meddle with.
> 
> ...


No problem BROTHER anytime.... 

hackery


----------

