Why does my Linksys E4200v2 router not detect my ATA?

[Scoponox]

I have a static IP on the ATA (Linksys PAP-2T) ...the router will only pick it up occasionally...most times it does not. The ATA is on and working (I can call in/out) but I can't see how the router can't find/see it.

I have added the ATA to the DHCP reserve list on the router but still nothing. I have the 5060 port forwarded for the ATA but when I go to canyouseeme.org it comes up as "Connection timed out"...because I think it can't see the ATA behind the Router.

Any help?

[Maxwell Smart]

I don't have your ATA, I have an OBi... but, for what it's worth, what I did on my ATA was to set it as dynamic (DHCP) but it was in the router's settings whereby I assigned a static IP for the MAC address of my ATA. It works fine as a result. If I did it the other way around, and went into the ATA's settings and changed it from dynamic to a static IP address and then reserved that IP address in my router, then it didn't work well... (so maybe try it the other way around if you can?) Just a thought anyway....

[dibsmft]

How to give a static depends on your router to some extent. If in doubt, I give the ATA a static address that is outside of the router DHCP range (thar should no larger than necessary). That usually works OK cases and long as you don't set the same static IP to more than one device! Forward ports 5061 and 5062 UDP to the ATA static IP and give Line 1 5061 and Line2 5062 as the SIP ports. You then need to forward the other ranges of ports that FPL uses to the ATA static IP.

[Scoponox]

dibsmft I had a hard time reading that...can you elaborate please? If i set the ATA out of the DHCP range doesn't that mean the router doesn't control it and it will be exposed?

[dibsmft]

Sorry, I posted it in a hurry because I had an important phone call. DHCP auto configures your ATA or other device and you don't have to reconfigure when your IP (or several other possible variables) changes. If you turn DHCP off on the ATA and fix the IP of the ATA outside of the DHCP range then the ATA will get that IP if not already used and keep the other settings that you put in. You can see this in my configuration for my Grandstream HT286 Screenshot.

[Scoponox]

Below are my settings on my router. I had set the ATA to 192.168.1.111 (in the range of the router)....but have now changed to 192.16.1.222 (out of the range) but the router still does not detect it either way; however, I wouldn't expect it to find it if its not in the range.

But I still don't understand why I would want to fix the IP of the ATA outside of the DHCP range...could you explain the reasoning please?

[dibsmft]

Looking at your DHCP server configuration, I think you have something wrong there. As it is enabled the DNS servers (at least two) should be showing there. Without those, while in DHCP mode, your ATA would not work because it cannot look up IP addresses.... I presume that those should be values (DNS 1 etc) that the router get from you provider. Your computer must be getting them..... check.... the computer setup and also the router status info. You may need to input the DNS servers that you wish to use here.
As I said, routers do things in various ways and some don't do some things very well. I check the information on the Cisco site but was not able to find anything useful. I did notice that the router does port triggering so perhaps you could use that.

[Scoponox]

DHCP is off in the ATA. I have port triggering and port forwarding set up on the router for the ATA.

Where would I get the DNS info from?

This stuff is starting to drive me nut...you have to be a network administrator to understand or get this stuff to work properly.

[dibsmft]

Most modern routers get IP addresses from DNS servers that your provider operates but there are others that can be used. Most routers run their own DNS cache so I usually set my network(s) up using the router DNS service and for your router the address is probably 192.168.1.1 so you could use that for the DNS server for the ATA or, if you like, the servers given to you by your ISP. Your router should be getting the external DNS servers if connects to the provider via DHCP which it should be doing.
Have you tried the ATA on a friends network to check that there is a problem with it.

"This stuff is starting to drive me nut...you have to be a network administrator to understand or get this stuff to work properly."
It is all very logical really and mostly things in voip are done in exactly (or close) to the way that you would expect them to be done. Your problem is most likely with the router which is a great router for Wifi and gaming but perhaps not so good for voip.

[Maxwell Smart]

DHCP is off in the ATA. I have port triggering and port forwarding set up on the router for the ATA.

Where would I get the DNS info from?

This stuff is starting to drive me nut...you have to be a network administrator to understand or get this stuff to work properly.

Well since you're failing at that, why don't you try turning the DHCP on the ATA "ON" and then in the router, assign a static IP address for your ATA based on it's MAC address?

[Scoponox]

I have changed the IP of the ATA out of DHCP range of the router. Still my router detects only when I first set up, and then it shows offline all the time.

Now using the DNS server from the ISP (Acanac...BTW they suck) for the router....DNS for the ATA is the router.

I really appreciate your guys time for explaining and helping out.

[Funkytown]

Now using the DNS server from the ISP Acanac.

DNS 1: 67.55.0.11
DNS 2: 66.49.220.95

These are the main two for DSL with that company.

[Scoponox]

Yes that is the what I have inputted in my Router.

I assume these are the correct settings for the ATA...my router being 192.186.1.1. of course.

[Funkytown]

Yes that is the what I have inputted in my Router.

I assume these are the correct settings for the ATA...my router being 192.186.1.1. of course.

I don't see your ISP DNS settings in the router in the picture you have provided, all I see is the DNS default of the router..
primary 192.168.1.1
Secondary 192.168.1.1
obviously these are not your ISP DNS settings.

[dibsmft]

The router should show the ATA as connected all the while. Something is not refreshing as it should? The route must have the external DNS settings or it could not work but they are not in the graphic ... perhaps they are elsewhere and the area in the graphic is intended for you to define other DNS servers of your choice.
The settings that Scoponox has all look OK..... I think. "NAT keep alive" should probably be set but if not then setting that might help keep the router awake.

[Scoponox]

Yes that is the what I have inputted in my Router.

I assume these are the correct settings for the ATA...my router being 192.186.1.1. of course.

I don't see your ISP DNS settings in the router in the picture you have provided, all I see is the DNS default of the router..
primary 192.168.1.1
Secondary 192.168.1.1
obviously these are not your ISP DNS settings.

I think this is what your looking for:

[Scoponox]

The router should show the ATA as connected all the while. Something is not refreshing as it should? The route must have the external DNS settings or it could not work but they are not in the graphic ... perhaps they are elsewhere and the area in the graphic is intended for you to define other DNS servers of your choice.
The settings that Scoponox has all look OK..... I think. "NAT keep alive" should probably be set but if not then setting that might help keep the router awake.

NAT keep alive is on already...

[Scoponox]

I should mention that my modem (2wire 2701HG-G with QWEST firmware) has IP address: 192.168.0.1....maybe this is where I am wrong?

I just tried accessing my mode via http://192.168.0.1/ but for some reason I can't get to it ...actually if I hook up directly to the modem (not router) and do ipconfig; I get nothing for the default gateway....something weird is going on. (Update: figure out how to access modem: need to set my laptop with static IP of 192.168.0.x, and then connect via wire to modem, and then can get to 192.168.0.1).

But after reseting my modem (and leaving the router alone)...ATA showed up as "Online" and then a few minutes later "offline" again

[blair.sutherland]

Everything is probably fine. First let's get some of the important networking questions answered.

I have a static IP on the ATA (Linksys PAP-2T) ...

The ATA is on and working (I can call in/out) but I can't see how the router can't find/see it.

Since you statically assigned your IP address, there is nothing for your router to manage (other than the CAM and PAT tables - these are behind the scenes), so that is why it's ok that it's not showing up in the router interface. The only reason why your ATA, or any other device for that matter, would show up on your router's interface is if it was in the DHCP pool as a registered client.

...the router will only pick it up occasionally...most times it does not.

That's an interesting one! Since the static address was originally in the DHCP scope, the router probably tried to assign that IP address to another machine at the end of a DHCP lease cycle. This is a common occurrence in networking, and there is code in modern consumer routers to prevent this from being an issue. In a nutshell, the router does a lookup to the Dynamic NAT (PAT) and ARP table, found an entry for that IP address, marked it as being already assigned, and went onto the next IP address.

Back in the day (on both consumer and commercial routers), this would have caused a traffic storm, where packets would have been split between machines, each requesting the missing packets. This would quickly escalate to a denial of service for either one or both devices, or perhaps the entire subnet.

There is also code in the networking stack of most modern OSs that prevent this, including even the firmware on the ATA. Windows, Linux and OSX would show a popup saying there's an IP address conflict. The ATA would just report the error to it's log.

I have the 5060 port forwarded for the ATA but when I go to canyouseeme.org it comes up as "Connection timed out"...because I think it can't see the ATA behind the Router.

All Cisco/Linksys consumer routers ship with "reply to external ping" or WAN ICMP respond turned off by default. To enable go to Security > Firewall > Block Anonymous Internet Reqeusts, uncheck and save. Don't leave this enabled - prob the fastest way to get hacked.

If I set the ATA out of the DHCP range doesn't that mean the router doesn't control it and it will be exposed?

Unless you explicitly set an IP address to be treated as a DMZ or statically assign port forwarding to a port that's vulnerable to hacking (say, port 3389 on your PC's IP address) or some such firewall exception, the router will, by default, not translate any incoming traffic from the internet through the router to that IP address. Consider yourself secure.

But I still don't understand why I would want to fix the IP of the ATA outside of the DHCP range...could you explain the reasoning please?

One of the rules to follow when assigning a static IP address is to use an address that is outside of the DHCP pool. This avoids a layer 3 addressing conflict, whereby more than one machine identifies themselves by the same IP address.

Looking at your DHCP server configuration, I think you have something wrong there. As it is enabled the DNS servers (at least two) should be showing there. Without those, while in DHCP mode, your ATA would not work because it cannot look up IP addresses.... I presume that those should be values (DNS 1 etc) that the router get from you provider. Your computer must be getting them..... check.... the computer setup and also the router status info. You may need to input the DNS servers that you wish to use here.
As I said, routers do things in various ways and some don't do some things very well. I check the information on the Cisco site but was not able to find anything useful. I did notice that the router does port triggering so perhaps you could use that.

Oops! That isn't where the e4200v2 shows the current DNS servers it received from the ISP, only where you'd set static DNS servers if you wanted to use 3rd party DNS! To see that we'd want to see a screenshot of the "Status" page.

That being said, since Scoponox is able to post on this forum (presumably from a computer behind the router, connected either via Ethernet or Wifi, configured via DHCP), we can assume internet connectivity and DNS operate correctly on the router. Also since the screenshots are posted from the web interface, we know the ATA is behaving properly from a pure-networking (OSI layers 1-3) standpoint.

I should mention that my modem (2wire 2701HG-G with QWEST firmware) has IP address: 192.168.0.1....maybe this is where I am wrong?

I just tried accessing my mode via http://192.168.0.1/ but for some reason I can't get to it ...actually if I hook up directly to the modem (not router) and do ipconfig; I get nothing for the default gateway....something weird is going on. (Update: figure out how to access modem: need to set my laptop with static IP of 192.168.0.x, and then connect via wire to modem, and then can get to 192.168.0.1).

But after reseting my modem (and leaving the router alone)...ATA showed up as "Online" and then a few minutes later "offline" again

Nope, still ok. Your modem is operating in router mode. If you connect to it directly and change it to bridge mode, it would be more efficient. In it's current state it's on a different subnet from your PC on the other side of a NAT gateway, so they should not be able to communicate with each other directly unless you enter a static route to each other on both the modem and router.

It's all good!

[dibsmft]

All true as far as I can deduce.
My router uses static IPs for all the permanently used devices outside of the DHCP(25-50 in the range (2 -24) and occasional devices use DHCP (25 - 50). All of the connected devices show as connected in the router and so should any router I would have thought (though with routers it is easy to be wrong!). Yes, it became clear that the empty DNS listing from the router could not be the DNSs that the router was using. It is a great help when answering questions to actually have the same devices but it rarely seems to happen . Thanks for joining in Blair.

[Scoponox]

Thanks for the informative responses!

What I am worried about is that if the router doesn't pick up the ATA then the QoS and portforwarding/triggering may not be working properly. If I anable the QoS with ATA set as the highest priority everything slows down.

I may be being stubborn but I still think the router should detect the ATA...the router picks up everything else fine. As I mentioned, the router will detect the ATA from time to time, particularly if I reboot something....But it then quickly drops the ATA in the device list.

If I ping the ATA via the router it shows up just fine...

Traceroute seems ok too

Here are my logs...the first part I think is my utorrent

And yes the DNS listing is where you input it

Another thing to note, is that I have other ports forwarded and i can see them...but not the 5060 port with the ATA.

I am on the fence and getting rid of the Cisco E4200v2 and getting a ASUS Rt-N66U...the E4200 is goofy in that the Twonky server can't be upgraged or modified and has a cap of 8000 files, and too many other little things like this issue.

[Bing Kol]

If only you read Maxwell Smart's post, oh well!

Thanks for the informative responses!
...

I am on the fence and getting rid of the Cisco E4200v2 and getting a ASUS Rt-N66U...the E4200 is goofy ..., and too many other little things like this issue.

So now, on your mark, get set, JUMP!

***sorry I can't help you.

***edit
I'd like to make sure that you have set your 2wire modem/router to bridge mode. If not, you will have problems no matter what router you get...unless you know your way around configuring double NATs.

[cu2o2o2]

I should mention that my modem (2wire 2701HG-G with QWEST firmware) has IP address: 192.168.0.1....maybe this is where I am wrong?

...

Yes, that is one area where you are wrong. A modem gives you a public IP address, and a router gives you a private IP address such as 192.168.0.1.

Essentially, you are double-NATed. Your modem has its router dishing out 192.168.0.1 and your E4200 192.168.1.1.

If you do not know your way around double-NAT configurations, you must set your 2wire modem to bridge mode (as mentioned), effectively disabling the 2wire's router function.

[Scoponox]

Yes the modem is in transparent bridge modem. Pppoe is from the router.
Is there anyway to check if double Natting?

[cu2o2o2]

I should mention that my modem (2wire 2701HG-G with QWEST firmware) has IP address: 192.168.0.1....maybe this is where I am wrong?

...

Doesn't your above statement tell you that your 2wire is doing PPPoE?