Airport Express extremely slow over NAT/DHCP

Fzang

Fzang

macrumors 65816
I live in a dorm where using the internet requires one to log in. I have set up an Airport Express in my room and set it to DHCP/NAT which enables me to log in one and then use wifi freely on all my devices. However, this gives insanely slow wifi speeds.

If I connect directly with bridge mode I get lightning fast internet, but then I can only use one device at a time, and I have to go through a lot of logging in/out troubles to use a different device.

I have tried every possible configuration I could think of... Can anyone give me some pointers?
 
Fzang said:
The router doesn't say anything about double NAT issues though. Not a problem then, is it?
Click to expand...

When you have two routers in a single chain you have a double NAT issue. The speed issue is likely occurring as the upstream router is throttling your port. Another possibility is that running a double NAT firewall is causing the problem. Older AirPorts would let you use DHCP to distribute addresses without using the NAT function. I doubt that is still an option.
 
Altemose said:
When you have two routers in a single chain you have a double NAT issue. The speed issue is likely occurring as the upstream router is throttling your port. Another possibility is that running a double NAT firewall is causing the problem. Older AirPorts would let you use DHCP to distribute addresses without using the NAT function. I doubt that is still an option.
Click to expand...

It does have a DHCP-only mode. However, I was under the impression that NAT is absolutely required for one-IP-per-login systems commonly used in dorms and public hotspots?
 
Fzang said:
It does have a DHCP-only mode. However, I was under the impression that NAT is absolutely required for one-IP-per-login systems commonly used in dorms and public hotspots?
Click to expand...

Not necessarily. DHCP would give one IP to the AirPort and create a separate DHCP range for clients connected to it. The DHCP option is under the "Network" tab correct?
 
Altemose said:
Not necessarily. DHCP would give one IP to the AirPort and create a separate DHCP range for clients connected to it. The DHCP option is under the "Network" tab correct?
Click to expand...

Correct.

If I set router mode to DHCP-only and try to update, I get

"Sharing a range of IP addresses using DHCP Only requires manually configuring your WAN IP address. If your ISP gives you a range of static IP addresses, you should manually configure your base station with the first IP address and distribute the rest via DHCP."

So I should connect via "static" instead of DHCP? Which IP addresses should I use? With DHCP my IPv4 is set to 210.77.14.38; should I put this in static instead?
 
Fzang said:
So I should connect via "static" instead of DHCP? Which IP addresses should I use? With DHCP my IPv4 is set to 210.77.14.38; should I put this in static instead?
Click to expand...

Yes. Copy all of the information and input that in as static.
 
Altemose said:
Yes. Copy all of the information and input that in as static.
Click to expand...

I've tried several combinations now, and I'm finding that

Static + bridge mode = good speed
DHCP + bridge mode = good speed
DHCP + NAT/DHCP = terrible speed
Static + DHCP = no connection
Static + NAT/DHCP = no connection

Maybe I'm doing this wrong? :confused:
 
Fzang said:
I've tried several combinations now, and I'm finding that

Static + bridge mode = good speed
DHCP + bridge mode = good speed
DHCP + NAT/DHCP = terrible speed
Static + DHCP = no connection
Static + NAT/DHCP = no connection

Maybe I'm doing this wrong? :confused:
Click to expand...

They are using an upstream router with a clear policy against routers as they "segment" the network. Your best option would be to manually log in on all devices or use the campus Wi-Fi if available.
 
Altemose said:
They are using an upstream router with a clear policy against routers as they "segment" the network. Your best option would be to manually log in on all devices or use the campus Wi-Fi if available.
Click to expand...

That's too bad. At least I found my problem :eek:

I can only connect with one device at a time (hence the reason I wanted to use NAT) or it'll ask for login and kick off the previous device. But I guess fast internet for one device is better than unusably slow internet for several devices :D
 
Fzang said:
That's too bad. At least I found my problem :eek:



I can only connect with one device at a time (hence the reason I wanted to use NAT) or it'll ask for login and kick off the previous device. But I guess fast internet for one device is better than unusably slow internet for several devices :D
Click to expand...


Unfortunately you are at the mercy of the network engineers and administrators at your school. Though, if they do not want wireless routers or APs they should have a strong ubiquitous network.
 
Altemose said:
Unfortunately you are at the mercy of the network engineers and administrators at your school. Though, if they do not want wireless routers or APs they should have a strong ubiquitous network.
Click to expand...

I study as a foreign student in China, and some things are just a bit slower here. Internet is one of them.
 
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