Airport Exteme in chain with ISP router

[stanthony]

Hi all!

I have an annoying problem and I hope to get some advice.

Currently I am using my Airport Extreme in bridge mode plugged after my ISP’s modem/router. DHCP is handled by my ISP’s modem/router (which is Thomson TG789vn). However, it has a strange problem/defect: if a device leaves a wireless network (e.g. phone or notebook) when it comes back it always connects, but sometimes will not have any Internet access. Reconnecting several times and/or providing it with a permanent IP on the network usually helps, but not for long. With no Internet access the devices are still visible on the local network and I can browse their content if I wish.

It is interesting that absolutely no problems arise in case of wired LAN connection, even if the client device is switched off for some time and then switched back on – it just works as supposed to.

I figure it is a DNS problem of the ISP’s modem/router (some sort of bug in the firmware maybe), but my ISP will not recognize the problem and even worse – the issue persists after replacement of ISP’s router/modem. I live in the countryside and do not get to choose between ISPs, so I am stuck with this one.

My idea was to try and make Airport Extreme a DHCP/DNS server for my network, but I am not sure how to do that. Essentially I want to build a chain with two routers: ISP’s router/modem provides IP address and DNS to my Airport Extreme, and Airport Extreme in turn provides IP addresses and DNS to all other devices on the network. Can I do that? If yes, please briefly explain how to set up my Airport Extreme accordingly.

Many thanks in advance!

 

[Bruno09]

My idea was to try and make Airport Extreme a DHCP/DNS server for my network, but I am not sure how to do that. Essentially I want to build a chain with two routers: ISP’s router/modem provides IP address and DNS to my Airport Extreme, and Airport Extreme in turn provides IP addresses and DNS to all other devices on the network. Can I do that?

Yes you can do that, but before I would suggest a test :

With the Airport Extreme (AE) still in bridge mode, use Airport Utility to set a static IP address (*) to the AE (Internet tab).

In "DNS server", instead of using the local IP address of your router, use a valid DNS of your ISP.

Let us know the following infos if you need more help :
- ISP
- local IP address of your ISP's router (192.168.1.1 for example)

(*) even when using DHCP, you can enter a DNS manually.

 

[stanthony]

Yes you can do that, but before I would suggest a test :

With the Airport Extreme (AE) still in bridge mode, use Airport Utility to set a static IP address (*) to the AE (Internet tab).

In "DNS server", instead of using the local IP address of your router, use a valid DNS of your ISP.

Let us know the following infos if you need more help :
- ISP
- local IP address of your ISP's router (192.168.1.1 for example)

(*) even when using DHCP, you can enter a DNS manually.

Thanks for your quick reply!
Attached is the screenshot of my AE Utility (I am using it on Windows atm).
With "Using DHCP" mode enabled I can't seem to be able to change the IP address to static, only can do that when I switch to "Manually" mode. On the other hand, I don't think this will help, since my AE always gets the same IP anyways (configured on the ISP's modem side). And I already have valid DNS information of my provider typed in. Doesn't work.
My ISP is Elion, I live in Estonia, EU, but I doubt this info will help

 

[Bruno09]

You can change to a Static IP address by clicking on "Using DHCP".

But this is not important, especially if the AE gets a fixed IP address from the router.

Back to the DNS : you currently are using : 192.98.49.8, and 192.98.49.9
Please note that I can't neither ping nor traceroute these servers, which suggests that they are down or do not exist.

I suggest :

1. try using 192.168.1.1 only instead.

2. check on Internet that 192.98.49.8, and 192.98.49.9 are the DNS your ISP is currently using. (I don't think so).
If you found news ones, enter the new ones.
I have tested : 213.168.18.146 and 195.50.193.163, they do work for me.
http://www.tcpiputils.com/browse/ip-address/213.180.31.128

3. If 1. and 2. do not work, use OpenDNS : 208.67.222.222 and 208.67.220.220

 

[blueroom]

Why not put the Thompson in gateway mode and just use the AEBS as a router?

 

[Bruno09]

Why not put the Thompson in gateway mode and just use the AEBS as a router?

This would not solve a DNS problem : you still need valid DNS servers, or you will not be able to access the Internet.

 

[stanthony]

You can change to a Static IP address by clicking on "Using DHCP".

But this is not important, especially if the AE gets a fixed IP address from the router.

Back to the DNS : you currently are using : 192.98.49.8, and 192.98.49.9
Please note that I can't neither ping nor traceroute these servers, which suggests that they are down or do not exist.

I suggest :

1. try using 192.168.1.1 only instead.

2. check on Internet that 192.98.49.8, and 192.98.49.9 are the DNS your ISP is currently using. (I don't think so).
If you found news ones, enter the new ones.
I have tested : 213.168.18.146 and 195.50.193.163, they do work for me.
http://www.tcpiputils.com/browse/ip-address/213.180.31.128

3. If 1. and 2. do not work, use OpenDNS : 208.67.222.222 and 208.67.220.220

OK, now to the weird part... The DNS that is indicated in my AE is the DNS that my ISP router/modem uses. Attached are screenshots of the ISP modem config screens. First one shows those exact DNS addresses, and the second one shows connectivity test for those DNS (passed).
I cannot change the DNS settings on the ISP modem (it obtains them automatically somehow and there is not Config button or anything for DNS).
Maybe that once again points to the fact that my ISP has some weird issues with DNS addresses? I've been using these very DNS addresses for about a year. Internet is perfect on all wired machines and ONLY wireless devices seem to loose Internet connectivity...
I am confused, to be honest.
If I point my AE's DNS to the ISP modem, the result will be the same, since ISP modem uses these same ones.
But if I type in the OpenDNS in AE will it work? I think it will still use the DNS of the ISP modem, no?

And as to the suggestion to put the ISP modem/router in bridge mode - I am not sure I can even do that. There are no options to change on the modem side that would suggest that.

 

[Bruno09]

1. If I point my AE's DNS to the ISP modem, the result will be the same, since ISP modem uses these same ones.

2. But if I type in the OpenDNS in AE will it work? I think it will still use the DNS of the ISP modem, no?

3. And as to the suggestion to put the ISP modem/router in bridge mode - I am not sure I can even do that. There are no options to change on the modem side that would suggest that.

Weird, indeed.

1. you are correct

2. If you type in the OpenDNS, it should use the OpenDNS.

3. you don't even need to put the ISP's modem-router in bridge mode to use the AE as main router.
But this would not solve a DNS problem...

Again, try using : 213.168.18.146 and 195.50.193.163, they do work for me.

For info, I can ping your gateway :
PING 90.191.216.1 (90.191.216.1): 56 data bytes
64 bytes from 90.191.216.1: icmp_seq=0 ttl=49 time=213.620 ms
64 bytes from 90.191.216.1: icmp_seq=1 ttl=49 time=244.547 ms
64 bytes from 90.191.216.1: icmp_seq=2 ttl=49 time=254.829 ms
64 bytes from 90.191.216.1: icmp_seq=3 ttl=49 time=282.837 ms
64 bytes from 90.191.216.1: icmp_seq=4 ttl=49 time=240.141 ms

But I can't ping your DNS.

 

[blueroom]

This would not solve a DNS problem : you still need valid DNS servers, or you will not be able to access the Internet.

IMHO OP's setup is more complex than it needs to be. As for the DNS try Google's 8.8.8.8 & 8.8.4.4

You can also override/set DNS on the client computers.

 

[stanthony]

Tried several things, mkay...

If I change DNS settings on AE to ANYTHING rather than those 192.98.49.8 and 192.98.49.9 (that should not even work), I get no Internet access on any devices, including wired ones (configured in DHCP mode, i.e are pointed to AE as DNS server).
BUT - if I leave AE alone and manually configure client devices themselves, I can use any DNS address (OpenDNS, Google ones, my ISP ones, etc).
The key thing is that in such case devices use AE merely as a switch (bridge?) and for all other intents and purposes work with ISP modem.
I would be happy with such config, no matter how faulty logic it uses, but then I hit my initial problem of randomly loosing Internet access on wireless devices.
I am a bit lost, if I am honest...

----------

Oh, and I've just tried pinging the 192.98.49.8 DNS and it works for me (sends bytes back)...

 

[Bruno09]

How did you setup your wifi network(s) ?

Do you use the AE only, the ISP device only, or both ?

 

[stanthony]

Will try to explain:

ISP DSL modem/router (Thompson) gets the signal from outside. It has 4 lan ports on the back. Two are used by TV boxes (the modem also provide digital TV services), one is used by a lan cable leading to the AE.
AE is set into bridge mode, so it would essentially be obsolete in this config, but I like using 5 GhZ mode of AE (my Thompson only allows 2.5 GhZ speeds of WiFi).
I have my wired devices (my main PC, NAS drives, etc) plugged into AE. I have my wireless devices using WiFi network created by AE. You've seen my AE Internet tab above (it worked in this state for over a year now).
IP/DNS/Gateway configs for Thompson and AE are in the post above.
My main PC and NAS use manual IP configs (for VPN purposes), other devices get IP automatically via DHCP.
For the record - if I create a wireless network on the Thompson and connect my wireless devices to it I will eventually get the same random failure to access Internet, as I am getting from AE WiFi.

----------

Oh. And in case of DCHP wireless devices point to 192.168.1.1 (Thompson) as DNS.

 

[Bruno09]

Ok, fine.

So, the only devices that randomly lose internet access are the wireless devices, using DHCP, right ?

The wired devices using static IP adresses do not have issues, right ?

What is the DHCP range of your ISP router (192.168.1.10 to 192.168.1.100 for example) ?

What are the static IP adresses used by the AE, your PC, your NAS,etc ?

Are they all outside of the DHCP range ?
Or may be they are inside the DHCP range, but reserved to a specific device ?

 

[stanthony]

I will check out tomorrow and revert with more info.
Thank you for trying to help me out with this problem! It is very kind of you!

 

[Bruno09]

You are welcome.

I suspect something is wrong in your ISP router setup.

Using the AE as main router and DHCP server would likely solve the problem.

However I think it interesting to try understanding what is wrong at the moment.

 

[eduardrw]

I have a similar setup with a ATT uverse gateway.
Modem/gateway connectetd to:
-- TV's
-- Airport Extreme in DMZ -- all devices (wired and WIFI).

See if you can put your AE in the DMZ. That means the TV's etc will still work however there will be effectively no router in front of your AE.

Here is a link describing it - just use AE instead of PC as the device.
http://help.spark.co.nz/app/answers/detail/a_id/20201/~/dmz-mode---thomson/technicolor-modems
(your device might be different)

I see in your screenshots that you up/downloaded 1TB/300GB in 20 days did you get throttled?

As for DNS servers - there is a program from Google which checks the best available DNS servers for your network and reports back suggested IP's for you setup based on access time.
https://code.google.com/p/namebench/

 

[stanthony]

I am back and I have answers to your questions

So, the only devices that randomly lose internet access are the wireless devices, using DHCP, right ?
Not really, ANY wireless devices may randomly lose internet access, even if I use manual setup for them and fix their IPs. All my wired devices have the fixed IPs for VPN purposes and never ever have experienced this issue. I strongly suspect though that they will not have any issues with DHCP either (it just may take too long to control, since this problem is really pretty random).

The wired devices using static IP adresses do not have issues, right ?
That’s right, but see above.

What is the DHCP range of your ISP router (192.168.1.10 to 192.168.1.100 for example) ?
192.168.1.64 to 192.168.1.254.

What are the static IP adresses used by the AE, your PC, your NAS,etc ?
AE - 192.168.1.68
Wired desktop PC - 192.168.1.70
NAS - 192.168.1.167

Are they all outside of the DHCP range ?
All WITHIN the DHCP range, actually.

Or may be they are inside the DHCP range, but reserved to a specific device ?
When I first encountered the problem I tried using IP address reservation on ISP router for ALL my devices (wired AND wireless). It did not help: wired continued working as before, wireless still had this random “no Internet” thing.

I suspect something is wrong in your ISP router setup. Using the AE as main router and DHCP server would likely solve the problem. However I think it interesting to try understanding what is wrong at the moment.
Yeah, I am interested in understanding this, too. However, if nothing helps my very first question still stands: how do I setup AE as the main router and DHCP server in pair with my ISP router/modem?

See if you can put your AE in the DMZ. That means the TV's etc will still work however there will be effectively no router in front of your AE.
Sorry, I am not that tech savvy What is DMZ, how do I put AE in this mode and how will I benefit from it? I am a bit confused about the link you provided.

I see in your screenshots that you up/downloaded 1TB/300GB in 20 days did you get throttled?
Nah, it is just my usage pattern these days: I mostly use browsing, email, some youtube streaming and MMOs, while heavily seeding many torrent files. It is normal at the moment

 

[Bruno09]

The DHCP range is 192.168.1.64 to 192.168.1.254

And you are using these static addresses :

AE - 192.168.1.68
Wired desktop PC - 192.168.1.70
NAS - 192.168.1.167

I would first change the DHCP range to 192.168.1.200 to 192.168.1.254 so that none of your static IP devices is within the DHCP range.

64 and 68/70 are very close, so you likely have IP address conflicts.

As for your very first question : "how do I setup AE as the main router and DHCP server in pair with my ISP router/modem?", this is very easy : just select "DHCP + NAT" instead of bridge mode.
I do not know if this would be ok for the VPN, though.

 

[stanthony]

Thanks! I will trying setting up my ISP router this way and see what happens.

As to the other option (AE as the main router): my AE utility has three options (as seen on the attached screenshot). Do I use the "Share a public IP address" then? Do I have to change something on my ISP router, too?

 

[Bruno09]

Do I use the "Share a public IP address" then?

Yes you are correct, this is the right option in your Airport Utility, or in Mac Airport Utility 5.6 as well.
"DHCP + NAT" is in the new Mac Airport Utility.

Sorry for that.

Do I have to change something on my ISP router, too?

There are two ways here :

1. do not change anything
The AE will be set as router + DHCP server, using another IP adresses range (10.0.1.x or 172.16.1.x)
You will get a "double NAT" warning, (blinking amber light), this is normal, and you can choose to "ignore" the warning, if so the light will turn solid green.

2. use the ISP modem router as modem only : you need to disable the router mode and the DHCP server.
Not all models allow this, for example I can NOT use my ISP modem router in bridge mode.
This does not prevent me from using an AE as main router if I want.

 

[stanthony]

Many many thanks for your help, Bruno09!

I will explore these options and will let you know of the results (may take some times though)
Thank you for your assistance once again!

 

[h9826790]

If it's DNS problem, all you need to do is manually enter the DNS address. You can do this in any OSX computers or iDevices.