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Contributor
Posts: 16
Registered: ‎09-24-2005
Accepted Solution

Setting a Fixed IP address on local LAN

Can someone tell me how to set up my home network to have fixed IP addresses on my local LAN.  I don't need a fixed IP address from Comcast. I just want fixed IP addresses for each of the computers on my local LAN

 

I have a Linksys WRT54G WiFi router, two computers, a NAS, a network printer that are hard wired to the router and one laptop that connects to my local LAN via wifi.  I have Win XP Pro PS3.

 

What I  tried to do was this:

 

On one of the computers I experimented with changing the Local Area Connection from "Obtain IP address automatically" to "Use the following UP address." I did this by:  clicking on Control Panel (Category View), Network and Internet Connections, and then "Network Connections.Then I right clicked on the Local Area Connection 4, scrolled down to the IP Protocol and clicked on it, and then clicked on Properties.  I then changed the first option only from "Obtain IP address automatically" to "Set IP address to" and set it to 192.168.1.150.  I chose this IP address to be outside of the range of DHCP addresses, which I understand can go as high as 192.168.1.149.

 

I left "OBtain DNS Server Address Automatically" as is.

 

I did not make this change in my other computer.

 

This did not work. I cannot connect to the Internet from this computer.

 

What did I do wrong?

Most Valued Poster
jenhome
Posts: 520
Registered: ‎09-25-2003

Re: Setting a Fixed IP address on local LAN

DHCP can assign from  from .1 to .255.   You need to go into your router interface (192.168.1.1) and set the router to reserve the address you chose for the computer so it doesn't assign that to DHCP.  You will also need to set the DNS server manually on the computer.  DNS is assigned by the DHCP server and if you bypass the DHCP you need to set the DNS server as well.   Set the DNS to the same settings as you see for DNS on the router. 

Connection Expert
JamesR
Posts: 6,433
Registered: ‎09-29-2007

Re: Setting a Fixed IP address on local LAN

1.   Does the Computer that you did not change still work?

2.  Can you do a ipconfig /all and post the results back here in your thread?

 

Email Expert
Posts: 18,241
Registered: ‎04-27-2004

Re: Setting a Fixed IP address on local LAN

Some routers can assign DNS servers when not assigning IPs, but I also have a WRT54G and in my experience it doesn't have this feature.

 

You can login to the router, see what DNS servers Comcast has assigned to it, and then copy these into your DNS server settings. I've had some problems using the router as my DNS server; it's supposed to work, but some types of queries seem to time out.

Contributor
Posts: 16
Registered: ‎09-24-2005

Re: Setting a Fixed IP address on local LAN

In Network Connections, IP Protocols, I manually set:

 

IP Address =  192.168.1.21     (I set my other computer to .22, and a third one to , 23.

 

I also manually set the DNS Servers = 68.87.73.246   and 68.87.71.230

 

I got these DNS server addresses.

 

My network works fine so far.

 

My only question is how long will these DNS Server addresses remain active? I persume they are Comcast addresses. Doesn Comcast ever change them?

 

My IPCONFIG follows:

 

John Wirt

 

C:\>ipconfig /all

Windows IP Configuration

        Host Name . . . . . . . . . . . . : CLIENT700
        Primary Dns Suffix  . . . . . . . :
        Node Type . . . . . . . . . . . . : Unknown
        IP Routing Enabled. . . . . . . . : No
        WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection 4:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . .  : Intel(R) PRO/1000 MT Network Connection
        Physical Address. . . . . . .  . : 00-15-17-B3-CB-4D
        Dhcp Enabled. . . . . . . . . . . : No
        IP Address. . . . . . . . . . . . : . 192.168.1.20
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        IP Address. . . . . . . . . . . . . : fe80::215:17ff:feb3:cb4d%4
        Default Gateway . . . . . . . . . 192.168.1.1
        DNS Servers . . . . . . . . . . . : 68.87.73.246
                                                     68.87.71.230
                                                     fec0:0:0:ffff::1%1
                                                     fec0:0:0:ffff::2%1
                                                     fec0:0:0:ffff::3%1

Tunnel adapter Teredo Tunneling Pseudo-Interface:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : . . . Teredo Tunneling Pseudo-Interface
        Physical Address. . . . . . . . . : . 80-00-30-39-BA-05-2A-6D
        Dhcp Enabled. . . . . . . . . . .  . : No
        IP Address. . . . . . . . . . . . . . . : 2001:0:4137:9e74:8000:3039:ba05:2a6d
        IP Address. . . . . . . . . . . . : . . . fe80::ffff:ffff:fffd%5
        Default Gateway . . . . . . . . . : ::
        NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter Automatic Tunneling Pseudo-Interface:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : . .Automatic Tunneling Pseudo-Interface
        Physical Address. . . . . . . . . : C0-A8-01-14
        Dhcp Enabled. . . . . . . . . . . : No
        IP Address. . . . . . . . . . . . : . fe80::5efe:192.168.1.20%2
        Default Gateway . . . . . . . . . :
        DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                                     fec0:0:0:ffff::2%1
                                                     fec0:0:0:ffff::3%1
        NetBIOS over Tcpip. . . . . . . Disabled

C:\>

Contributor
Posts: 16
Registered: ‎09-24-2005

Re: Setting a Fixed IP address on local LAN

So far,  (one day) the Comcast DNS Server addresses have worked fine.

 

Contributor
Posts: 16
Registered: ‎09-24-2005

Re: Setting a Fixed IP address on local LAN

[ Edited ]

See above.

Contributor
Posts: 16
Registered: ‎09-24-2005

Re: Setting a Fixed IP address on local LAN

[ Edited ]

I have included the IPCONFIG output above..

Connection Expert
EG
Posts: 43,665
Registered: ‎12-24-2003

Re: Setting a Fixed IP address on local LAN


jwirt wrote:

 

I also manually set the DNS Servers = 68.87.73.246   and 68.87.71.230

 

I got these DNS server addresses.

 

My network works fine so far.

 

My only question is how long will these DNS Server addresses remain active? I persume they are Comcast addresses. Doesn Comcast ever change them?

 


FWIW, in the not so far future they will be changing to their DNSSec offerings which will be 75.75.75.75 and 75.75.76.76

More on DNSSec here; http://www.dnssec.comcast.net/faq.htm

Connection Expert
JamesR
Posts: 6,433
Registered: ‎09-29-2007

Re: Setting a Fixed IP address on local LAN

you can do an NSLOOKUP on thoseserver addresses at the Command prompt.

> nslookup 68.87.73.246

> nslookup 68.87.71.230

Email Expert
Posts: 18,241
Registered: ‎04-27-2004

Re: Setting a Fixed IP address on local LAN

 


EG wrote:

 

FWIW, in the not so far future they will be changing to their DNSSec offerings which will be 75.75.75.75 and 75.75.76.76

More on DNSSec here; http://www.dnssec.comcast.net/faq.htm


 

My guess is that when Comcast decides to make DNSSEC standard, they'll update all the other DNS servers to use it, not redirect everyone to the 75.75.x.x servers. So the current IPs should continue to work.

 

But what you can do is occasionally check the DNS servers that your router shows, and make sure that your manual configuration matches them.