On Tue, 17 Jun 2008 01:34:45 Jerry Feldman wrote:
On Mon, 16 Jun 2008 19:58:35 +0930
Rodney Baker
wrote: Yes, you can use both wireless and wired ethernet but not both to the same network - they must be in different subnets or you will generate routing loops
I disagree here. I have configured multiple interfaces on the same subnet many times. You certainly need a unique IP address. I have used both static and dynamic IP addresses. There may be only 1 default route.
It can be done but you must be careful not to cause routing loops. IMHO it is best avoided unless you are conversant in IP networking and know how to use the right tools to troubleshoot if you run into problems. It can even be useful for redundancy and bandwidth sharing purposes, which is where things like STP (spanning tree protocol) and RIP come into play but I wouldn't recommend it to a networking novice.
I have also had occasions to have multiple subnets on the same physical segment. I currently run a couple of servers where we have 5 IP addresses, which 2 or 3 assigned to physical machines, and the others assigned logically to the primary interface.
I commonly do this on my laptop where I have to plug into different networks in different physical locations for testing and maintenance purposes. Having multiple IP's for the same interface (all on different subnets) helps to reduce the need to reconfigure at each location...
One issue here is that you can only have 1 host name associated with an IP address, and this is where having a combination of static and dynamic addresses work.
I disagree with that statement. You can have multiple hostnames associated with a given ip address and multiple ip addresses (on different networks) associated with the same host name for a multi-homed machine, however each machine can only be configured locally with a single hostname. To illustrate my point, run `dig mail.iinet.net.au` and `dig smtp.iinet.net.au`. Both names resolve to the same IP address. You can have multiple host names with dns entries pointing to the same IP address, just as you can use multiple aliases for a single address in /etc/hosts. You would not, however, use multiple entries in /etc/hosts with the same host name pointing to different ip addresses - that simply wouldn't work. The only way that I'm aware of to have multiple different IP's (in different subnets) for the same host is if they're on different networks and registered wtih different dns servers that are specific to each network (or have individual entries in /etc/hosts for each client on the various subnets). This would only be useful, however, if there was otherwise no connectivity between the different networks; after all, that is what routers are for. Of course, the same applies to having multiple subnets on the same physical segment with mutiple logical addresses assigned to the one interface. -- =================================================== Rodney Baker VK5ZTV rodney.baker@iinet.net.au =================================================== Flugg's Law: When you need to knock on wood is when you realize that the world is composed of vinyl, naugahyde and aluminum.