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Author Topic: Why can't ping a wireless broadband modem?  (Read 5168 times)

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Offline orange

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Why can't ping a wireless broadband modem?
« on: February 25, 2009, 09:19:20 AM »
Could be a really really noob question, please don't laugh at me.

I am using this Sierra Wireless Raven XT for this weather station. It uses DDNS and hyperterminal to connect to it. Couldn't work, so I try to test my concept using a household USB wireless broadband modem with dynamic IP sim card the one you see every kid is using.

So I connect the household modem to my PC. Connect it up to internet. IPCONFIG shows:

IP Address....10.240.151.128
Subnet Mask....255.255.255.255
Default Gateway....10.240.151.128

Ping no problem on the PC connected to the ordinary wireless modem.

So i went to another PC with another internet connection and PING 10.240.151.128, and lo! No response! Why is that???  #-o :oops: :oops:

Is my concept wrong some where? How to ping that household wireless modem from another PC?  #-o :oops: :oops:

Advance thanks!

Offline Peter1949

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Re: Why can't ping a wireless broadband modem?
« Reply #1 on: February 25, 2009, 01:29:58 PM »
There are 2 basic things (other than an incorrect set-up) which can prevent PINGS. 1 ) the device may not respond to PINGS. 2) a firewall might not let PINGS through. I wasn't quite sure with your set-up whether your first successful PING reply was on the same PC in which case it might have been a 'loopback' reply you received, in other words it didn't actually go anywhere outside your PC.

If you are using Windows you could try using TRACERT ip address (from the Command Prompt), this should give you a step by step reply and enable you to see where it is getting stuck. DDNS suppliers and ISPs have also been known to block PING requests. See below a successful example of PING to a public DNS server

C:\Documents and Settings\Peter.MyPC>tracert 158.43.192.1

Tracing route to cache0003.ns.eu.uu.net [158.43.192.1]
over a maximum of 30 hops:

  1     2 ms     1 ms     1 ms  10.10.30.4
  2    58 ms    61 ms    58 ms  dr13.ennby.ov.easynet.net [89.200.128.198]
  3    60 ms    57 ms    57 ms  5acf001e.bb.sky.com [90.207.238.30]
  4    59 ms    59 ms    59 ms  be2.er10.txlon.ov.easynet.net [195.66.226.43]
  5    60 ms    61 ms    59 ms  ge5-0.BR1.LND8.ALTER.NET [195.66.226.16]
  6    61 ms    61 ms    59 ms  so-2-3-0.CR2.LND8.ALTER.NET [158.43.254.37]
  7    62 ms    73 ms    62 ms  ge-1-0-0.XR2.LND9.ALTER.NET [158.43.252.46]
  8    61 ms    61 ms    61 ms  POS2-0.GW9.LND10.ALTER.NET [158.43.150.129]
  9    60 ms    59 ms    59 ms  ge-0-0-0.lnd10eusoesr2.lnd.ops.eu.uu.net [158.43.150.114]
 10    62 ms    61 ms    62 ms  cache0003.ns.eu.uu.net [158.43.192.1]

Trace complete.
Regards
Peter

Offline niko

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Re: Why can't ping a wireless broadband modem?
« Reply #2 on: February 25, 2009, 01:36:26 PM »
Looks like you have a router, not just a modem. 10.240.151.128 is an IP assigned to the PC on your private/local network on your side of the router. The router has its own public IP on the internet side. If you want to ping the router from some other connection you need to know that public IP. The simplest way to get that is to browse to www.whatismyip.com from a PC on your local network. Many routers have a configuration option to not respond to a ping, but if it does allow ping you should be able to ping it using that IP from other PC's connected to the internet. The router routes traffic from the public IP to and from the local IP's of the connected PC's using "Network Address Translation"  (NAT).

I suggest you search on "Router", "Network Address Translation" or "NAT", and "Port Forwarding" to get a better understanding of how the internet and your network are working.

Offline Peter1949

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Re: Why can't ping a wireless broadband modem?
« Reply #3 on: February 25, 2009, 01:48:41 PM »
Well spotted Niko. I missed that very relevant point which pretty much confirms the first 'successful' PING was a loopback reply.
Peter

Offline niko

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Re: Why can't ping a wireless broadband modem?
« Reply #4 on: February 25, 2009, 01:56:21 PM »
First time I can recall seeing a 10. IP from a consumer router.

Offline Peter1949

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Re: Why can't ping a wireless broadband modem?
« Reply #5 on: February 25, 2009, 02:12:49 PM »
That's also true. Normally 192.168... range. Unless the guy/gal that did the coding for the chip decided it was a good idea to be different and have a DNS range starting with 10 (or the device was previously used in a commercial environment and the system administrator changed it). Mustn't side-track 'orange'. None of this is really revelant to his problem, your advice to check www.whatismyip.com still stands.

Peter

Offline JaxWeather

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Re: Why can't ping a wireless broadband modem?
« Reply #6 on: February 25, 2009, 07:09:38 PM »
Zoom uses 10.x as well really screwed me up when I switched to using a Zoom router/modem...

-Bob

Offline orange

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Re: Why can't ping a wireless broadband modem?
« Reply #7 on: February 26, 2009, 09:51:07 AM »
Guys thanks for the answer. I did two more tests (EDIT: with the ordinary household broadband USB modem that every kid used, not the Raven XT) and noticed two things, please correct me if I am wrong:

1. I used what is whatismyip.com and got back an IP. I pinged the IP from another PC and there is no response. So the model i am thinking is that the IP is actually referring to the public IP of the private network of my modem.  But once the ping packet reached the private network public IP, it doesn't contain further information to be forwarded to the local(smaller/baby/sub :oops: ) IP contained in the private network, that's why I cannot get a response. Is my concept model correct at this point? Is there some kind of further setting required that specify the local IP forwarding something like this:  >ping 119.234.1.24:10.240.151.128


2. The other test I did was use two modems and sim cards from the same network provider, hook them up to two PCs. IPCONFIG one modem and get the local IP address in the private network.  Then from another PC (with another sim card from same network provider) ping the IP I got from IPCONFIG. No response. So now I am thinking the modems probably is ping blocked, because both of the modem is already connected to their same private network with their local IP and they should be able to easily find each other sitting on the same highway. :oops: So is my concept correct here?

Advance thanks.

   
« Last Edit: February 26, 2009, 01:23:40 PM by orange »

Offline niko

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Re: Why can't ping a wireless broadband modem?
« Reply #8 on: February 26, 2009, 01:48:12 PM »
Guys thanks for the answer. I did two more tests (EDIT: with the ordinary household broadband USB modem that every kid used, not the Raven XT) and noticed two things, please correct me if I am wrong:

1. I used what is whatismyip.com and got back an IP. I pinged the IP from another PC and there is no response. So the model i am thinking is that the IP is actually referring to the public IP of the private network of my modem.  But once the ping packet reached the private network public IP, it doesn't contain further information to be forwarded to the local(smaller/baby/sub :oops: ) IP contained in the private network, that's why I cannot get a response. Is my concept model correct at this point? Is there some kind of further setting required that specify the local IP forwarding something like this:  >ping 119.234.1.24:10.240.151.128

To access a PC behind a router on a normal broadband connection you can use port forwarding (see my post above). That means you set up a rule in the router so that if it sees any traffic on a defined port, e.g. 1234, it will send it to a defined PC, e.g. 10.240.151.128. Then you would add that port number to the public IP so 119.234.1.24:1234. You can use this for remote access, FTP, a webserver, and other services, but ping will not take a port number, so you cannot ping through the router.

Quote
2. The other test I did was use two modems and sim cards from the same network provider, hook them up to two PCs. IPCONFIG one modem and get the local IP address in the private network.  Then from another PC (with another sim card from same network provider) ping the IP I got from IPCONFIG. No response. So now I am thinking the modems probably is ping blocked, because both of the modem is already connected to their same private network with their local IP and they should be able to easily find each other sitting on the same highway. :oops: So is my concept correct here?

Could be, I have no idea how cell type networks work, but someone else may. Probably would help if you tell us where you are and what network this is.

Offline orange

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Re: Why can't ping a wireless broadband modem?
« Reply #9 on: February 26, 2009, 02:22:00 PM »
I am in Singapore using M1 and Singtel wireless network. M1 is a partner of Vodaphone, UK,  and their wireless network system could be the same.

Singapore is a first world country with the no 1 concentration of millionaires in the world in 2006. So i guess the wireless network system here should not be too much different from the wireless system of UK, USA and Australia.

I had a chat with M1 representative, here is roughly what I learn from him about static IP:
"Wireless network in Singapore cannot have public static IP, it can only have private APN static IP. But we cannot connect with ordinary internet connection to the wireless private APN static IP, we must use another wireless modem with m1 sim card in the same private APN  to connect to the wireless private APN static IP, that means two wireless modem is required to connect to each other."

But in my case i am using dynamic ip, not sure if the above still applies. But I did test no 2 with two wireless modems, still dont work.

The ordinary household USB modem i am testing is designed for plug and play, with very simple GUI with close to nothing settings. So there is no setting for ping blocking or port forwarding.

Thank you.

Offline prodata

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Re: Why can't ping a wireless broadband modem?
« Reply #10 on: February 26, 2009, 05:04:33 PM »

"Wireless network in Singapore cannot have public static IP, it can only have private APN static IP."

TBH I'm not 100% sure that I'd believe that, but maybe Singapore is different. In the UK, it's certainly possible to get mobile (cellphone) SIMs with a public static IP. But to get one you typically have to go to a specialist data provider. The ordinary cellphone droids know very little about this service and so typically you get the answer that it can't be done. As an example see:

http://www.nucleusnetworks.co.uk/mobile-broadband/3g-static-fixed-ip.htm

There's some significant cost associated with this service - certainly it's not as cheap as having a standard mobile dynamic address, but it's not outrageously expensive either - you're looking at maybe US$20-25 per month for a bandwidth allowance of 1-3GB.
John Dann
www.weatherstations.co.uk - UK Davis specialists

Offline niko

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Re: Why can't ping a wireless broadband modem?
« Reply #11 on: February 26, 2009, 05:26:52 PM »
Singapore is a first world country with the no 1 concentration of millionaires in the world in 2006. So i guess the wireless network system here should not be too much different from the wireless system of UK, USA and Australia.

I suspect it's a lot better  :lol:

Re: Why can't ping a wireless broadband modem?
« Reply #12 on: March 13, 2009, 01:42:32 PM »
Ace manager gives you the possibility to enter a modem name and domain. (use eairlink as domain, see manual).  Because my cellular provider provides me a dynamic ip we use modemname.domain to connect to the modem. ping command gives me an ip address.

I think it's better not to use an ip address because it's dynamic.


My problem at the moment is a wireless connection is not possible. But I don't know why. Is there anyone who was succesfully connected wireless to the wireless modem (raven xt)? Please tell me how you did this.

Re: Why can't ping a wireless broadband modem?
« Reply #13 on: March 18, 2009, 11:54:12 PM »
Ace manager gives you the possibility to enter a modem name and domain. (use eairlink as domain, see manual).  Because my cellular provider provides me a dynamic ip we use modemname.domain to connect to the modem. ping command gives me an ip address.

I think it's better not to use an ip address because it's dynamic.


My problem at the moment is a wireless connection is not possible. But I don't know why. Is there anyone who was succesfully connected wireless to the wireless modem (raven xt)? Please tell me how you did this.

Any help would be very much appreciated

Offline niko

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Re: Why can't ping a wireless broadband modem?
« Reply #14 on: March 18, 2009, 11:59:21 PM »
You might do better on a networking forum.