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ADSL Bridge frustration

V

Vlad

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I have a ADSL "modem" that I want to configure and use but its giving me a hard time and it doesn't seem to make any sense. (To me anyway) I have all of the ATM and DSLAM settings correct, or atleast I'm 98% sure I do but the problem is it will give me an IP address, but the modem can't ever find the default gateway. It's interface shows me it knows the line speed, it gets a WAN IP and everything else BUT the gateway IP never shows up.
But if I use the shoddy ISP issued one it all goes fine. The ISP one isn't altered in any way from the manufacturer and I can log into its interface to look at the settings. They should be identical but I might have gotten something wrong but I have no idea what. I've checked multiple times and haven't found anything different yet.

Does anyone have any idea what I'm doing wrong or whats going on?
 
Can you spoof the MAC in the non-ISP provided modem? They might have your circuit limited to a particular MAC address.
 
kb2syd said:
Can you spoof the MAC in the non-ISP provided modem? They might have your circuit limited to a particular MAC address.
Click to expand...

I can but it requires I use telnet to access a low level shell of some kind. I don't think they limit it to a MAC address since I've had to exchange the ISP issued one five times over the years since they just stop working for arbitrary reasons. The only thing I've ever had to do was a DHCP release before unplugging the malfunctioning one.
 
Vlad said:
I have a ADSL "modem" that I want to configure and use but its giving me a hard time and it doesn't seem to make any sense. (To me anyway) I have all of the ATM and DSLAM settings correct, or atleast I'm 98% sure I do but the problem is it will give me an IP address, but the modem can't ever find the default gateway. It's interface shows me it knows the line speed, it gets a WAN IP and everything else BUT the gateway IP never shows up.
But if I use the shoddy ISP issued one it all goes fine. The ISP one isn't altered in any way from the manufacturer and I can log into its interface to look at the settings. They should be identical but I might have gotten something wrong but I have no idea what. I've checked multiple times and haven't found anything different yet.

Does anyone have any idea what I'm doing wrong or whats going on?
Click to expand...

There are a handful of settings you might need to mimic between the DSL modems (I could be familiar with either or both units, if you tell me what they are):

Is your ISP modem set to PPPoA or PPPoE?

You have a Dynamic IP from your ISP?

Encapsulation (something like "VC-MUX" or "LLC/SNAP")

Protocols ("MMODE", "G.dmt", "G.lite", etc.)

VPI/VCI: Typically values like 0 and 32

ISPs typically arrange their DSL Dynamic IP pools to have the gateway as the first address of the class-C block (x.x.x.1), but it can be set up different ways too...
 
The ISP issued one is a Starbridge Lynx L-220 (I hate these with a passion) And the one I'm trying to use is a Trendnet TDM-C400.

They don't use either PPPoA or PPPoE, its just set to get everything from automatically. Although I'm confused now and have to go look since that doesn't sound right.

The IP addresses are assigned via DHCP.

As far as I know Encapsulation is LLC.

Protocol wise its G.dmt

VPI/VCI is 0 and 32

I know the default gateway since when use the Starbridge its listed in the router and it is x.x.x.1

I'm going to go look at the Starbridge's settings, it has an awkward interface so I might have over looked something.
 
Under the section where it has PPPoA and PPPoE its just set to Bridge. From the looks of it all it does is bridge the 2 connections and gets assigned everything though DHCP. Encapsulation is LLC/SNAP.
 
Vlad said:
...As far as I know Encapsulation is LLC.

Protocol wise its G.dmt

VPI/VCI is 0 and 32

I know the default gateway since when use the Starbridge its listed in the router and it is x.x.x.1...
Click to expand...

These setting sound very standard...

I'm not familiar with either modem brand...

Since you seem to have these settings down, it has to be other areas of the configuration...
 
Vlad said:
Under the section where it has PPPoA and PPPoE its just set to Bridge. From the looks of it all it does is bridge the 2 connections and gets assigned everything though DHCP. Encapsulation is LLC/SNAP.
Click to expand...

Do you have this hooked to a router? I ask because usually "bridge mode" is used when a DSL modem is hooked to a router which handles the PPPoE login. If you don't have a router (or a PPPoE set up in software in your computer - (rare)), then Bridge would be the wrong choice.

Who is your provider? I might can look them up and figure out the right settings. (I'm a reformed former DSL helpdesk guy)
 
I do have a Linksys router but when I'm trying to get it to work its just hooked to a laptop so I can see its interface. But even if I do hook it to the router it still doesn't do anything. As far as I know they don't use PPPoE. My ISP was Gallatian River, which was owned by Madision River but the whole mess was bought by CenturyTel although nothing seems to have changed though that oddessey.

I'm starting to think kb2syd might be right, last night it seemed to act like the DSLAM was blocking it but when I have to exchange the poorly made modems, they're all factory sealed so they didn't alter its firmware that I'm aware of. For all I know they might record the MAC addresses and block 3rd party ones since the settings between the two are identical. I'd call tech support and ask but they generally act like like the information is Top Secret and it usually boils down to "turn it off and back on" or "exchange the modem".
 
Vlad said:
I do have a Linksys router but when I'm trying to get it to work its just hooked to a laptop so I can see its interface. But even if I do hook it to the router it still doesn't do anything. As far as I know they don't use PPPoE. My ISP was Gallatian River, which was owned by Madision River but the whole mess was bought by CenturyTel although nothing seems to have changed though that oddessey.

I'm starting to think kb2syd might be right, last night it seemed to act like the DSLAM was blocking it but when I have to exchange the poorly made modems, they're all factory sealed so they didn't alter its firmware that I'm aware of. For all I know they might record the MAC addresses and block 3rd party ones since the settings between the two are identical. I'd call tech support and ask but they generally act like like the information is Top Secret and it usually boils down to "turn it off and back on" or "exchange the modem".
Click to expand...

Sounds like it might be MAC based (PPPoA). If you had PPPoE, you would have a username and password that you would have to put in the modem or router. But to connect it directly to a PC I think you will still need to take it out of bridge mode. In that mode the modem will not try to authenticate to the network properly.
 
But factory sealed dosen't mean Murky River Telephone doesn't know the MAC address, or at least the MAC preamble. The first so many octets of the MAC address (used to?) identify the manufacturer.

Most of the equipment I own has the MAC address printed on the outside of the shipping box. It is usually near the FCC ID, SKU or barcode.
 
kb2syd said:
Most of the equipment I own has the MAC address printed on the outside of the shipping box. It is usually near the FCC ID, SKU or barcode.
Click to expand...

Yep, there's a tiny sticker with a barcode listing its MAC address I overlooked. Since Trendnet told me how to change the MAC on theirs I might clone the one on the Starbridge anyway just to see what it does.
 
shawn510 said:
Sounds like it might be MAC based (PPPoA). If you had PPPoE, you would have a username and password that you would have to put in the modem or router. But to connect it directly to a PC I think you will still need to take it out of bridge mode. In that mode the modem will not try to authenticate to the network properly.
Click to expand...

The manual that came with the ISP issued one says if you want to directly hook it to your computer to either use the USB cable or the included ethernet cable, which is just a regular patch cable so it doesn't appear to matter.
 
Well that ended in disaster. After checking the settings of both several times I've come to the following conclusions:


  • The Trendnet modem does not work properly
  • DSLAM's can lock you out if irritated by something
  • Starbridge isn't that bad after all
  • Mocha is actually pretty good

I ended up getting blocked all together by the DSLAM because of the MAC address tom foolery and Tech Support said if I unplug everything and wait four hours the DSLAM would allow access again. Apparently its a security function of some sort. So with no Internet access I went for a coffee to settle down. I might see if NewEgg will take the Trendnet modem back since I've had enough of it.

Big thank you to everyone in this thread for the wisdom and advice! :)
 
Vlad said:
Under the section where it has PPPoA and PPPoE its just set to Bridge. From the looks of it all it does is bridge the 2 connections and gets assigned everything though DHCP. Encapsulation is LLC/SNAP.
Click to expand...

Typically ¨Bridged Mode¨ is only used on a Static IP, where no PPPoA/PPPoE username and password is needed. The ISP shouldn´t use the MAC address just in the scheme that it adds more overhead on their Tech Support. I guess it is a moot point now.

I´ve been able to get a number of DSL modems working with the service that is my $DAYJOB$...
 
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