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#16 +BudMan

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Posted 06 December 2012 - 19:57

Not sure what you mean by tried the first few? To access your modems interface? Why would it be on your private side?? Most cable modems default to 192.168.100.1 - I can access mine from my 192.168.1.0/24 network.

But this is not always the case. So are you using chrome, and you get this error?
Error 324 (net::ERR_EMPTY_RESPONSE): The server closed the connection without sending any data.

Now with my router I don't have any issues

modemaccess.jpg

But here is why you can have problems depending on what your router does. This is what you have


internet---modem (192.168.100.1) --- (publicIP.23.42.x) router (192.168.1.1) ---- (192.168.1.100) PC

So even if your modem is listening.. You run into this issue, your router has NO ipaddress on the 192.168.100.x network, it has a public IP on the interface that is connected to the modem. With say a gateway of publicIP.24.42.254 or something while your router has IP publicIP.24.42.67 that it got from your ISP.

Now your computers on the 192.168.1 network have a gateway of 192.168.1.1 -- your router. so when they try and go to say 24.45.16.42 or something... They know its not on the 192.168.1.0, so they send it to your router at 192.168.1.1, he says I don't have that network locally connected so it sends it to its gateway (your isp). That publicIP.24.42.254 address in my expample. Well that gateway is sure not going to know how to get to 192.168.100.1

So you get an error. Now depending on your router, you might be able to configure it to be able to talk to your modem 192.168.100.1 address even though it doesn't have an interface in that network. For example, with pfsense here are instructions on talking to the modem interface from behind pfsense

http://doc.pfsense.o...inside_firewall

it comes down to pretty much giving your router a VIP on its wan in the 192.168.100 network so it knows how to talk to your modems IP.

So some routers work, other don't - but like you said you should really not need to access your modems interface. If you do, connect your PC to it, and give it an address on the 192.168.100.x network.


#17 Koshur

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Posted 11 December 2012 - 15:35

If you do, connect your PC to it, and give it an address on the 192.168.100.x network.

+1
Makes more sense, one of the reasons you might ever want to access your modem page is in case you want to bypass and enable bridging your connection. Other than that you would seldom be accessing it.

#18 +BudMan

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Posted 11 December 2012 - 16:34

Cable modems are almost always bridged - if they do nat then they would be called a gateway not a "modem" ;)

One reason I could see to access is to verify what firmware you have installed from your ISP, and or signal strengths, view logs for errors and such. Only time I have accessed it is when doing screen shots for other users or if something off in connection to check signal levels, etc.

#19 Koshur

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Posted 11 December 2012 - 16:57

My bad.. Obviously I was pointing to "ADSL modems" (i use one), totally forgot he's using a cable modem.

#20 +BudMan

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Posted 11 December 2012 - 17:36

Which brings up an issue I have with terminology that some makers use.. If the thing does NAT, then don't freaking call it a modem, call it a gateway if it has ability to connect to isp network, be it dsl, cable, cell, fiber or even sat, etc. and does NAT or can do NAT. If it can not do nat and just provides connection then its a modem, if it does nat and has ethernet for wan and lan then call it a router.

If these different terms were not wrongly interchanged then everyone would know the features your working with depending if you say you have a modem, router or gateway ;)

What gets me is when users say their "modem" when they are really talking about a gateway or router. If it can do NAT then its not really a modem ;) If you have a gateway and have just turned it into a bridge, then its a gateway in bridge mode, etc. etc..

For example uses say they are directly connected to their "modem" But that is really a router, and then they have a gateway in front of it so they are double natting, sometimes even triple natting and can not figure out why port forwarding works, etc. Because they added a wireless router to the mix and instead of using it as AP, they plugged it into their network using its wan, and now its also natting, etc. etc.

Good indication if its gateway or router is if it has more than 1 lan port. But in the DSL world, you see many gateways with only 1 lan port, etc. I really can not recall the last time I saw just a true dsl modem - they are almost always gateways these days. Some support bridge mode, others are locked into doing nat.

#21 +warwagon

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Posted 11 December 2012 - 20:39

Which brings up an issue I have with terminology that some makers use.. If the thing does NAT, then don't freaking call it a modem, call it a gateway if it has ability to connect to isp network, be it dsl, cable, cell, fiber or even sat, etc. and does NAT or can do NAT. If it can not do nat and just provides connection then its a modem, if it does nat and has ethernet for wan and lan then call it a router.

If these different terms were not wrongly interchanged then everyone would know the features your working with depending if you say you have a modem, router or gateway ;)

What gets me is when users say their "modem" when they are really talking about a gateway or router. If it can do NAT then its not really a modem ;) If you have a gateway and have just turned it into a bridge, then its a gateway in bridge mode, etc. etc..

For example uses say they are directly connected to their "modem" But that is really a router, and then they have a gateway in front of it so they are double natting, sometimes even triple natting and can not figure out why port forwarding works, etc. Because they added a wireless router to the mix and instead of using it as AP, they plugged it into their network using its wan, and now its also natting, etc. etc.

Good indication if its gateway or router is if it has more than 1 lan port. But in the DSL world, you see many gateways with only 1 lan port, etc. I really can not recall the last time I saw just a true dsl modem - they are almost always gateways these days. Some support bridge mode, others are locked into doing nat.


But it also acts as a DSL modem, so wouldn't a better term be "Modem router combo!"

#22 +BudMan

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Posted 11 December 2012 - 20:42

yes a modem/router combo is a "gateway"

http://en.wikipedia....dential_gateway

#23 Mando

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Posted 11 December 2012 - 22:09

What does that mean? The default address is 192.168.1.1.

I have no idea. It's a motorola SB5101U.

I think I'm starting to figure out what's going on. This doesn't work at all like a DSL modem. It only acts as a DHCP server while it's not connected to the internet; after that, it's just a bridge that gets a public IP address assigned from the ISP. So what I should probably do is set the router to act as DHCP server, disconnect it from the modem, reboot the modem, wait until it connects, and only then plug it into the router. Does that make sense? I'll try that asap.

as you say set the router to be your dhcp server and let the modem do its thing, Ive seen having to clone the Modems MAC address to the wireless router before I could gain net access from the wifi router. (last night infact on gfs mums Virgin UK link)

#24 +BudMan

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Posted 11 December 2012 - 22:52

"clone the Modems MAC address to the wireless router"

You mean clone the mac of the device that was connected before to the modem, say a different router or PC sure. But you wouldn't clone the modems mac to the router.

Sure if your isp has authed only a specific mac to talk to the modem, or you don't want to reset the modem to be able to connect a different device to clear the modems cache, sure. But that is not what the user is talking about - I went over the issue already. Once his router gets a public IP address, how would it know how to talk to a 192.168.100.0/24 address if its on say 24.13.1.0/24

#25 pes2013

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Posted 11 December 2012 - 22:56

@pes2013 the modem acted as a DHCP server because it did so by default, so I simply disabled DHCP on the router. Everything was connected into non-WAN ports because it just worked that way.

Then why not disable the DHCP server on the modem and let the DHCP server on the router be the active one?

That's where Im kinda of confused :\ Maybe you did it on purpose for something in particular...

#26 OP Andre S.

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Posted 11 December 2012 - 23:08

Thanks for the explanation budman, I think I'll just connect the modem directly to a PC if I ever need to check its config page, as you say this should be a rare occurence.

Then why not disable the DHCP server on the modem and let the DHCP server on the router be the active one?

That's where Im kinda of confused :\ Maybe you did it on purpose for something in particular...

Because then I'd have had to configure the modem (actually the gateway) in bridge mode and it becomes harder to access the gateway, as my current situation illustrates. When your modem is a gateway it's simpler to let it do its thing and not add any layer in front of it.

#27 +BudMan

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Posted 12 December 2012 - 12:47

I think there might be some confusion here on why the cable modem hands out 192.168.100.x addresses when your connected to it before its connected to your isp.

This is on configuration page of my cable modem. Look on yours, pretty sure its going to have the same kind of info.

DHCP Server Enabled
The SURFboard cable modem can be used as a gateway to the Internet by a maximum of 32 users on a Local Area Network (LAN). When the Cable Modem is disconnected from the Internet, users on the LAN can be dynamically assigned IP Addresses by the Cable Modem DHCP Server. These addresses are assigned from an address pool which begins with 192.168.100.11 and ends with 192.168.100.42. Statically assigned IP addresses for other devices on the LAN should be chosen from outside of this range


Notice the disconnected from the internet part. If it has a connection to internet, then it will NOT hand out these 192.168.100.x addresses and you will get a PUBLIC IP (normally) from your ISP. You never no your isp could be doing nat upstream.

I see my router do this sometimes if the internet connection is lost. The wan now gets a 192.168.100.x address, until the connection comes back and router tries to update its lease or you do a release and renew on your own. I would have to assume the lease on these 192.168.100 addresses is pretty low, check it next time you connect to your modem before it has sync'd your internet connection. Then look with ipconfig /all to see how long the dhcp lease it gave you was.

#28 pes2013

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Posted 12 December 2012 - 19:05

Because then I'd have had to configure the modem (actually the gateway) in bridge mode and it becomes harder to access the gateway, as my current situation illustrates. When your modem is a gateway it's simpler to let it do its thing and not add any layer in front of it.

OK :) If that's you perfered setup so be it! :)