DSL modem over digital

[marktwayne]

The other day, someone asked me to install a DSL modem and small Cisco router at their small office for some kind of connection to another business. When I arrived I found out they already had an ISP fiber optics line leading to a four line digital phone system and internet. I wasn't able to get it to work.

I haven't install a DSL modem for while. When I did, it was always over an old-style POTS line. Do DSL modems even work over such a digital setup?

I contacted the off-site company this office was trying to connect to, and they tried to configure the router to connecting to the already existing ISP connection. The lights to the local switch and WAN seemed to show that things were physically connected, but users were still not able to connect to the off-site company. My guess is that they tried to configure the router to use their own (the off-site companies) DNS servers and the ISP doesn't allow that.

To summarize my suspicions:
1) DSL modems don't work over most digital systems.
2) Many ISP's prefer users to use their own DNS servers and sometimes block access to others.

Am I clueless, or do my suspicions have some merit?

 

[john-b691]

DSL is DSL why would you think it works on something that is not DSL. That is why it also does not work on cable systems they use cable modems.

In this case you toss the modem in the trash and use the connection provided since that is standard ethernet. Mostly DNS works the other way around They block other people from using theirs. You can almost always get 8.8.8.8 or 4.2.2.2 to work, both these allow public access.

You would have to do much more testing to see if you actually have a internet connection or not. Although it is uncommon for them to block DNS it is common for them to lock the connection to a single mac address or require some form of logon via PPPoE. You would have follow their instructions on how to attach a router to the network to see if they have any special requirements.

 

[wacabletech]

The other day, someone asked me to install a DSL modem and small Cisco router at their small office for some kind of connection to another business. When I arrived I found out they already had an ISP fiber optics line leading to a four line digital phone system and internet. I wasn't able to get it to work.

I haven't install a DSL modem for while. When I did, it was always over an old-style POTS line. Do DSL modems even work over such a digital setup?

I contacted the off-site company this office was trying to connect to, and they tried to configure the router to connecting to the already existing ISP connection. The lights to the local switch and WAN seemed to show that things were physically connected, but users were still not able to connect to the off-site company. My guess is that they tried to configure the router to use their own (the off-site companies) DNS servers and the ISP doesn't allow that.

To summarize my suspicions:
1) DSL modems don't work over most digital systems.
2) Many ISP's prefer users to use their own DNS servers and sometimes block access to others.

Am I clueless, or do my suspicions have some merit?

1 Yes, the PBX/phone system is not going to support DSL. you would have to hijack a specific outlet and pair in their wiring room to do this.
2. Not many or prefer, it's not that common, some times when you FIRST hook a device up the DNS service on the device routes you to a provisioning page [aka DNS hijack] until you get provisioned, but that's about it. Its not just buy a dsl modem hook it up and off you go the ISP has to accept the device on to their network, this is generally called provisioning and they will want the MAC and model information at the least.

 

[marktwayne]

DSL is DSL why would you think it works on something that is not DSL.

If you read my message more carefully, you will find out that I suspected it wouldn't be compatible. However, we are living in a day of virtulization. A digital phone line could certainly be made to emulate a POTS line if one wanted, so I am not certain that no such system exists.