Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Airport extreme- bridge mode

timelessbeing

timelessbeing

macrumors 6502
Original poster
Oct 15, 2009
439
129
I turned off my connection sharing (bridge mode).
bridgemode.png


I was wondering, since the Airport is no longer a node on the internet, why does the configuration still allow me to enter TCP/IP information, and does it make a difference what I put in there?

Screen%20shot%202010-12-14%20at%205.03.25%20PM.png
 
Last edited:
Phil A.

Phil A.

Moderator emeritus
Apr 2, 2006
5,799
3,094
Shropshire, UK
Bridge mode doesn't turn off the connection, it turns off connection sharing, which basically stops the airport acting as a NAT router and DHCP Server (useful if you already have a NAT router / DHCP server that connects to the internet such as an ADSL router).
It still connects to the local network and still needs an IP address: its easiest to leave the IP configuration to getting an IP address via DHCP.
 
timelessbeing

timelessbeing

macrumors 6502
Original poster
Oct 15, 2009
439
129
I use bridge mode because my ISP now provides two dynamic IP addresses, and I have two computers. I'd rather not fuss around with NAT. That doesn't leave any automatic IP addresses for the Airport itself, so what TCP/IP settings should I use then?
 
Phil A.

Phil A.

Moderator emeritus
Apr 2, 2006
5,799
3,094
Shropshire, UK
I don't think there is a configuration for the Airport that would work like you want it to in that situation as the Airport requires an IP address itself (so you'd need at least 3 IP addresses). Why don't you want to use NAT?
 
timelessbeing

timelessbeing

macrumors 6502
Original poster
Oct 15, 2009
439
129
It does work because I've been using it this way for a while. It even seems to work with an illegal address like 127.0.0.1, which is why I'm wondering what the TCP/IP settings are good for. Doesn't bridge mode essentially turn the Airport into a hub? Hubs don't have IP addresses.

NAT is not perfect, and I have run into problems with sharing an IP address before. Port forwarding further complicates matters. I just prefer to have a simple and unhindered connection to the internet.
 
Last edited:
G

gigiuk

macrumors newbie
Jul 30, 2006
20
0
timelessbeing said:
It does work because I've been using it this way for a while. It even seems to work with an illegal address like 127.0.0.1, which is why I'm wondering what the TCP/IP settings are good for. Doesn't bridge mode essentially turn the Airport into a hub? Hubs don't have IP addresses.

NAT is not perfect, and I have run into problems with sharing an IP address before. Port forwarding further complicates matters. I just prefer to have a simple and unhindered connection to the internet.
Click to expand...

The TCP/IP settings in bridge mode are used for management purposes only, eg to connect to the base station via IP to configure and monitor it, for it to get network time etc. It doesn't do anything for the actual flow of data between your computers and the Internet. If you want to use bridge mode and you don't have a spare address for the BS you can just configure any address manually and leave it that way.
 
timelessbeing

timelessbeing

macrumors 6502
Original poster
Oct 15, 2009
439
129
Thanks gigiuk. That pretty much answers that question.

I have another about my wireless printer on the same Airport, which needs an IP address as well. Say I give it a private IP address 192.168.0.3, with subnet mask 255.255.255.0. If I give my macbook an IP address on the same subnet, like 192.168.0.4, it "sees" the printer just fine. But my macbook gets dynamic IPs from my ISP such as 66.x.x.x, or 77.x.x.x, which puts it outside of the printer's subnet, and it can no longer see it. Is there a way for my LAN devices to talk to each other, and access the WAN at the same time, without enabling DHCP or NAT?
 
Last edited:
G

gigiuk

macrumors newbie
Jul 30, 2006
20
0
timelessbeing said:
Thanks gigiuk. That pretty much answers that question.

I have another about my wireless printer on the same Airport, which needs an IP address as well. Say I give it a private IP address 92.168.0.3, with subnet mask 255.255.255.0. If I give my macbook an IP address on the same subnet, like 192.168.0.4, it "sees" the printer just fine. But my macbook gets dynamic IPs from my ISP such as 66.x.x.x, or 77.x.x.x, which puts it outside of the printer's subnet, and it can no longer see it. Is there a way for my LAN devices to talk to each other, and access the WAN at the same time, without enabling DHCP or NAT?
Click to expand...

No, there isn't with bridge mode and 2 addresses for 3 devices. The only solutions would be to wire the printer to the base station via USB or to get an extra address from the provider. What I personally would do though is use NAT as it also provides a layer of security and in your case you wouldn't lose the IP functionality of the BS. NAT does work okay and port forwarding is easy to configure via the airport utility.
 
timelessbeing

timelessbeing

macrumors 6502
Original poster
Oct 15, 2009
439
129
Hmm, that's too bad since the printer doesn't need to access the internet, only the other computers.

Extra IP's from Telus are $10. Not really worth it.

I tried connecting the printer via the USB port on the BS, and I can print from my MBP, but the iMac gets an error when trying to add the printer. Also, I lose the network scanning functionality. But that's whole other can of worms.

Security hasn't been an issue for me so far. NAT can actually weaken security, since it can't modify encrypted network data packets.

Yes, for most users, NAT works okay, but there drawbacks. (http://en.wikipedia.org/wiki/Network_address_translation, http://en.wikipedia.org/wiki/NAT_traversal) I have configured port forwarding before, and every once in a while one runs into problems with end-to-end connectivity, and just can't make it work. With the limited options the Airport gives you, it can be really frustrating.

I have a spare Gigaset SE567 wireless router from my ISP, and a hub lying around. Perhaps I can combine them somehow to make this work ...
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom