dummy ip adresses

[VJ]

Hello,

A weird question, but what IP address should I set if I don't want my computer to take part in the network?

The reason I ask is this: I us NetProfileSwitch to change settings for various networks. However, in order to activate a profile, you first need to physically connect to a network. During the time between connecting physically and activating the profile (which first flushes the information), the PC appears on the network (possibly with an incorrect IP address). So I want to add a profile in which all adapters are set to "neutral" (I can then activate this when I leave a network, and when I connect to a different network the PC won't participate).

I'm thinking of using either 0.0.0.0 or 127.0.0.1 .
(0.0.0.0 seems like a weird address to use in a normal network; 127.0.0.1 is unreachable for other networked devices)

Any suggestions?

Thanks!


Jörg

[lowlifecat]

127.0.0.1 or use an APIPA

[VJ]

APIPA is not suitable: my work network is constantly checked for unallowed IP addresses (and mac-addresses, but this doesn't matter here), so I need something that doesn't yield a network connection.

The 127.0.0.1 seems like a logical thought, but I also found that all addresses in the range 127.x.x.x are loopback addresses (http://www.geocities.com/SiliconVall...rk/ipaddr.html ). As 127.0.0.1 is the local loopback adapter, might it be perhaps better to go for 127.0.0.0 or so?


Jörg

[schmosef]

I assume that the networks you connect to do not all implement DHCP.

Otherwise (ie., if they did), you wouldn't need this profile switcher.

I wouldn't use the loopback IP. I would use something in the "Class C" range with a small (ie., one host) netmask.

For example: 192.69.69.1 with a netmask of 255.255.255.254 and no gateway.

[VJ]

True, but it is also useful when connecting to different networks that use DHCP: the PC tries to reuse its previous IP address, and does so even if this address is alreay in use on the network. Consequently, it yields an IP address conflict. The profile switchers flushes the IP settings prior to activation of a profile, making sure the IP address is not reused. It also switches smtp mail server, sets up a VPN if needed, alters firewall settings and sets or removes shares.

Why would you use something in the class C range?


Jörg

[VJ]

Just thought of something: the profile switcher also allows me to disable a network adapter. I'll have to test, but perhaps that is the easiest thing to do?


Jörg

[schmosef]

Why would you use something in the class C range?

Just in case you happen to one day use a piece of software that expect a semi legitimate IP address.

It doesn't really matter what you use if your netmask is so tightly constrained.

[schmosef]

Just thought of something: the profile switcher also allows me to disable a network adapter. I'll have to test, but perhaps that is the easiest thing to do?


Jörg

Uh, yeah. I assumed you already tried this approach and couldn't get it working.

[VJ]

Uh, yeah. I assumed you already tried this approach and couldn't get it working.

Sorry, my mistake... You cannot disable an adapter... You can only check whether or not it is altered in a profile. But the adapter has to be present.

So I need a workaround....

I understand why you'd go to Class C.... But isn't 127.0.0.1 a legit IP address as well (even though you won't get far with it)?


Jörg

[Helevitia]

There are private IP addresses that are recommended for use. See this page:

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

[VJ]

I know about those...
But I'm looking for an adress which can be used to have a non-functional network even though the pc is physically connected.

(it is to bridge the time before I can activate the profile)


Jorg

[Helevitia]

You can use anything then. Just pick a range of addresses like 192.168.100.1-254/24 and never use this range for anything else.

[VJ]

The networks I connect to are not all under my control. One uses 192.168.1.x, another 192.168.2.x, a third one uses 157.193.x.x.
I just wondered if there was an address that would not connect me to any network: if I were to choose 192.168.100.1 for instance, I could cause a conflict on a network which uses subnet 192.168.100.x. At the moment I don't connect to any such networks, but it could happen. If there exists a dummy ip address, I could use this one (hence the thought of using 127.0.0.1: no network device can see me; I don't think I could connect either).


Jörg

[VJ]

Well, setting 127.0.0.1 as an IP address does not work. There is no error message, but when verifying with ipconfig, it is obvious the addresses haven't changed.


Jörg

[schmosef]

the netmask is the important point here.

if you use a netmask that restricts you to one host, it doesn't matter what IP address you assign, even if it's an IP already in use on the main network.