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ip address shows on one & 198.154 on another

by erickp33 / July 14, 2006 6:21 AM PDT

I have 2 computers connected through a LAN. Both were working fine, but today, one of them dosent connect to the internet. It gives the IP address 169.254... on the one that is not working and 198.... on the one that is working. I would be grateful if someone could help me out .

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Sounds like you need a router.
by R. Proffitt Forum moderator / July 14, 2006 7:11 AM PDT

This is typical of a LAN connected to the internet. The 198.154.x.x is not a private IP that one would see on a router so that seems to be the problem. No router.


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If a router is in place.....
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Do you have a DHCP server?
by pratapan / July 15, 2006 4:01 AM PDT

Any time you see an IP address of 169.x.y.z, this is a default value that Microsoft uses when DHCP requests fail. I am not sure why they do this but it is common. I suppose all of the PCs could talk to each other despite DHCP being down. But most people want to communicate with the internet or a server so this has limited usefulness.

Use "ipconfig /all" at a DOS prompt. This will show your configuration in detail. Most routers act as DHCP servers. Sometimes wireless has problems with DHCP. This can be tested by configuring a unique static IP address in the same network range.

If your router/DHCP server assigns IP address like, Mask =, then every device in your network must share the same first 3 numbers in this address. 192.168.2.x is your network.
X can be a value between 1 and 254. So you can have up to 254 devices on this network.

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RE: 169...
by Visualdude / July 27, 2006 12:45 AM PDT

I can confirm that computers can talk to each other using what I have termed a MS fallback IP address. The problem with just letting Windows 2000 or later use a fallback address, is that the startup time is significantly longer because of the process used to determine a safe address to use. If you have computers that need to communicate, but you have no DHCP server, then set the IP configuration manually.

I mostly run into this at clients that have no internet access, or is limited to dialup on a single computer.

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configuring IP manually
by verdyp / July 27, 2006 5:05 AM PDT
In reply to: RE: 169...

don't configure IP addresses manually without taking an IP address available or the Internet, or using special reserved addresses.

The 3 safe spaces for configuring IP addresses manually is: to to to

These three spaces can only form 3 separate local networks. By default, hosts on one space (subnetwrok) cannot discuss to hosts on the other subnetwork, unless one of them is acting as a router.

Each address space starts and ends with a special address that must not be assigned to hosts but is used for broadcasts. The start and end of each subnetwork is determined by what is named a "network mask". The network mask is equal to the first address of the space, its lowest and last bits are all zeros, its first and highst bits are all ones.

For simplicity use the following addresses for hosts and netmask pairs:

* to for up to 24 millions PCs and routers on your LAN in the same subnetwork, netmask (generally this space is splitted into several subnetworks interconnected by routers and switch, in large private networks like universities or large organizations)

* to for up to 16382 PCs and routers, netmask
* to for up to 16382 PCs and routers, netmask
* to for up to 16382 PCs and routers, netmask
* to for up to 16382 PCs and routers, netmask
* to for up to 16382 PCs and routers, netmask

* to for up to 254 PCs and routers, netmask
* to for up to 254 PCs and routers, netmask
* to for up to 254 PCs and routers, netmask
* to for up to 254 PCs and routers, netmask

Generally, this last set with netmask is recommanded when you have a connection sharing on one router with a single IP address assigned by your ISP for your Internet access. Note that the router will have at least *two* addresses: the public IP on the internet side, and a private IP in the space of your LAN. 254 addresses for all PCs and routers on the LAN is ample enough for all home users today, unless one has lots of media appliances.

It's important that all hosts on the same LAN share the same netmask and that the IP addresses are in the same space. Your routers must also have an address configured in that space if you cant your PCs to reach them (notably is this is the router that connects them to the Internet).

Some routers that have Ethernet and WiFi connections for the LAN configure two separate private spaces for each connection type, so the router will have three IP addresses: one for Internet, one for local LAN on Ethernet, one for its builtin WiFi hotspot. The router will make the necessary interconection between the WiFi hosts and the Ethernet LAN, if the wired PCs on the LAN don't also have a WiFi adapter. It is much simpler to use such routers than configuring the correct routing options on a PC, notably because most routers presents you a simplified configuration wizard accessible from any browser, and that integrates most commoin configurations. Advanced configuration is possible through the alternate CLI interface (using telnet), or with special and costly management softwares based on SNMP and/or UPnP protocols.

Note: when choosing a rooter for home, you wmay want one that supports UPnP, because it will help Windows configuring the builtin firewall for compatibility with some softwares that need it. this is because the internet connection sharing changes the IP addresses and port numbers visible on the Internet or on the LAN, and that routing must be adapted to specify which host on the LAN will honor the traffic coming from a single public IP address from the internet on some distinct port number. Without it, some softwares will have difficulties to work (notably Peer-to-peer programs, instant messengers, media players), unless you manually configure the router with some complex rules, someting difficult to determine with compelx protocols like audio/video live streaming (based on dynamic UDP ports depending on the number of medias played in parallel).

With UPnP, your software installed on the PC can discuss with your router to correctly configure the needed routes and IP/port translations.

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I have the same problem??
by sss112 / July 24, 2006 12:45 PM PDT

I have the same problem. I have a wireless home network that was working fine until last Thursday 7/20/2006. I have a desktop connected to my ISP and a wireless router, a laptop that is left on all the time, and a work laptop that I connect occasionally.

The laptop I leave on worked fine, but when I tried to connect my work laptop over the weekend it wouldn't connect. I then rebooted the laptop I leave on and now it cannot get the proper IP.

Any ideas?

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How are you trying to connect?
by BubbaGee / July 26, 2006 9:03 PM PDT

You need to specify more information before anything can be diagnosed.

1st: Has the IT staff at work done any work on the laptop recently? They may have changed a setting or two that is interferring.

2nd: How do you connect the laptop at work and home, wireless at both, wireless at one, or wired at both? I typically connect via wire at work and wireless at home.

3rd: Do you have your router setup to assign the same IP to the laptop every time you connect or does it just use an available IP from its pool of addresses? I had problems with my router until I started assigning specified IP addresses to each system I connect to my network based on the MAC address of the cards.

4th: Are you running a wireless router in an area where neighbors are close and running computer? Someone may be hijacking some of you IP addresses.

If you can answer those questions then we may be able to help you.

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Router Reset?
by guardbeagle / July 27, 2006 2:33 AM PDT

The most likely cause is that your router has been reset, and is no longer providing DHCP services. I see this symtom regularly when the power goes out. If you know how, access your router's configuration via web browser. Simply enter the router's IP address in the URL address line of your browser. Each router has it's own standard IP address, but I can tell you Linksys uses (unless you changed it).

You will probably have to enter at least a password to access your router's settings, but hopefully you saved your documentation. If not, access the internet somewhere else and download (and print) the router's documentation from the vendor's website.

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IP Address 169.254
by jsheehy / July 26, 2006 6:50 PM PDT

The 169.254 IP address is the default IP address for a network card. This means that it hasn't received an IP address from a DHCP device. Cause, bad NIC, bad cable, bad connection somewhere, DHCP client not enabled on this computer, no DHCP provider available, and so on. Check your connections. connect the cable from the 198.154 computer to this computer and see what happens.

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by kbennett50 / July 27, 2006 1:01 AM PDT
In reply to: IP Address 169.254

This is what is called APIPA. Like the others have said, you get this when your computer is hooked to a network of some sort but can't communicate with DHCP. This is not a default of the NIC. If you didn't have LAN connection at all you wouldn't have any IP address.

What I'm confused about is you don't say if you're connected to a router or using ICS or a proxy of some kind so all anyone can do here is speculate.

I would start at the command prompts, do the loopback ping of to check the TCP/IP stack. If that works, then ping your own IP address. If you get replies, your NIC is good. If you send and don't get replies, the problem is with your NIC.

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No. 169.254.x.x only!
by verdyp / July 27, 2006 4:31 AM PDT
In reply to: 169.x.x.x

Not all 169.x.x.x is for local use on LANs and not routed on Internet. Only 169.254.x.x is APIPA and used to configure PCs on a LAN where there's no DHCP server available to configure their local IP address.

The 169.254.x.x space is allocated by choosing an address randomly in that space, and testing if no other host replies to this address with some ICMP PING. If some other host is present at this address, it will reply using his own address as the source and the collision of addresses will be detected and reported, so that the conflicting PC will reconfigure itself and select another address until there's no more conflict.

Normally, you can't reach any host on the internet with such a local address, and Internet hosts can't reply to you if you attempt to connect to them.

Look into RFCs, this address space is for local use only.

On the opposite, the addresses like 198.x.x.x that you have on one PC is the one you get from an ISP when your PC is initiating an internet connection. This address that your PC gets allows it to talk with other hosts on the web, but they can only reach your host, not the others on the LAN, unless the connected PC shares its connection on the LAN by acting as a router, and the other hosts on the LAN use your connected PC as a router.

Anyway, running is local router on a PC of the LAN is a bad idea. Today, routers are cheap, and most DSL routers sold today contain a router which performs itself the DSL connection to Internet and implement the conection sharing using a separate link to the LAN. They also implement a firewall to protect your LAN, and a DHCP server to configure hosts on the LAN instead of using the (lengthy) APIPA space which is not reliable.

Consider changing your DSL modem for a new one or buy a router; that's not so expensive and there are many advantages (including for your PCs that can boot much faster and work in a LAN easily, even when the Internet connection is not available for whatever reason). But remember that some Ethernet-to-Ethernet routers are sometimes more expensive to add, and more complicate to use, than just replacing the modem with a new model that has a builtin router.

What I said about DSL is also valid for Cable connections; there are Ethernet-to-Ethernet routers that know how to initiate a PPP or PPTP tunnel to connect to the Internet. Only that router will get a public IP address accessible from Internet. All hosts in your LAN will have a local-only (but stable) IP address configured very fast with the built-in DHCP server of the router. The router will also contain a DNS proxy, so that PCs on the LAN will not need to be configured for the DNS, even when the Internet connection is lost and reconected: the PCs on the LAN will use the router's local address as their DNS server, and this address won't change.

This also means that PCs on the LAN can be configured statically, with permanent IP address, fast boot time, permament connections to local services (like file shares, printers, multimedia servers, LAN supervision service, central management of various utilities, live discussions between hosts on the LAN...) without them being disconnected and reconnected and reconfigured when the router has its Internet connection temporarily closed and restarted.

Note also that many ISPs now offer the modem with builtin router, builtin WiFi hostspot, sometimes also a BlueTooth hostspot for connecting cameras or mobile phones, and some other services. Don't miss those great devices. Although their builtin firewall have limited functionality, they are extremely resistant to software attacks and can't be easily reconfigured by any virus that may exist somewhere on PCs of your LAN.

So this firewall (based on NAT routing, plus some builtin rules that are preconfigured to block the access to the most sensitive services running on your LAN like file servers, made inaccessible from the outside), is a great thing that will completely avoid your PC to manage most of the incoming traffic. You may still need a local software firewall, but this is only to protect against a few malwares that may be installed on the LAN (most often hidden in trojan programs).

The second interest is that the external router runs a different OS (not Windows, but most often VXworks or a limited Linux kernel, or a Cisco realtime OS, and in some cases, some routers integrate two parallel OSes with one running as a virtual service of the second one, for even greater security!) than your PC, so breaking into your PCs will requiring breaking two OSes with different design, something extremely difficult to target by virus and malwares.

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New Virus?

Try running the removal tools for the Look2Me virus.

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a little troubleshooting
by gemini54 / July 27, 2006 1:11 AM PDT

i am assuming that you have a router on your system.
i have had this happen quite a few times, although, usually all computers are affected. there are a few things you can try:
1. swap the connections from your router to each of your computers. if the problem moves to the other system, then you likely have a router problem.

2. reset your router by turning the power off and after about 30 seconds turn it back on

3. you can login to the router setup through your browser. just put the routers ip address in the address bar, for instance, mine is, which is quite common - you can find yours in the documentation that came with your router. once you get in to the router setup, you can do a release/renew operation of your internet connection.

4. if your problem did not move in step 1, you likely have a computer problem which could have many causes. a faulty nic, setup, driver, etc.
But try the first couple of things to try and determine where the problem is.

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Op configuration
by Mohammed Faizal / February 9, 2009 5:26 PM PST

no problem Is there is any DHCP server installed.Thn u change the lan ip properties TCP/IP change to Obtain automatically.Or give the same ip range ang geteway.Also the same preffered DNS ip.thn u pls check the proxy server if installed.

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