how to solve "DSL internet connection when connected to LAN"?

By funkworks ·

I am having a problem with my current setup. I have 1 Dedicated Line using a Cisco router 1841 and 1 DSL connection using normal router.

Two different ISP are configured with different gateways. When I use the first gateway using the Cisco router, my internet connection are all fine. But when I used the other gateway with the normal DSL connection it seems that my connection are dropping (intermittent connection or no internet at all). Given the users on my LAN are consist of 20 clients only.

I really needed to find what are the cause of this issue. I am thinking issue started with difference between modems. the normal DSL line is using a small normal modem hence the Dedicated line is using a bigger modem.


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All Answers

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Request for Clarification

by Walid AlMoselhy In reply to Clarifications

Do you have any hardware/software redundancy ISP depolyed. to use both internet connections you need to have one.

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Size of modem does not matter

by robo_dev In reply to how to solve "DSL interne ...

what is your 'normal' router/modem? what make/model?

How are your workstations connected to two routers? E.G. is there an ethernet switch in-between>?

Which router works as the DHCP server for the workstations? (if the answer is 'BOTH' then that's your problem).

Is DHCP enabled in both routers?

A DSL connection is a dial-on-demand service, but you can configure your router to keep the connection active at all times.

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Reponse To Answer

by funkworks In reply to Size of modem does not ma ...

Thank you for the answers.

The "normal' modem model is ZyXEL P-600 Series. and I am using the Linksys RV016 for that.

I am using Cisco Catalyst 2960 Switch for the workstation connections and for the two routers.

I have a dedicated Windows Server 2003 for DHCP. disabled DHCP for both routers.

How do I configure the router in keeping the connections active at all times?

Another thing, I found out that when someone is using torrent application like uTorrent the connection of my DSL is dropping but why the dedicated line doesn't?

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Couple of ideas

by robo_dev In reply to how to solve "DSL interne ...

First of all, the Zyxel is a router, and a router (RV016) behind another router means you do double-nat, which is slow and less reliable, mostly because the secondary router is a DHCP client of the first router. Some things just will not work through double-NAT, such as a VPN.

Also, I would assume the DSL connection/login is configured in the Zyxel and it is configured to only maintain the connection for a certain period of time. If you get into the admin interface of the Zyzel, you can change the DSL timeout (but again, having the Zyxel work as a router with the RV016 behind it is not a good thing).

The best solution is to either re-configure the Zyxel so it is set to 'bridge mode' so it works as a DSL modem, and configure the RV016 to login and establish the DSL PPOE connection. This should work more reliably.

Alternately, just get rid of the RV016 and use the Zyxel, as it most likely has a standard NAT firewall.

Torrent applications sometimes cause connections to fail for one of three reasons. First of all, they make TONS of socket connections all at once which can trigger a security feature in the router, can sometimes overload the memory of the router, and sometimes even the ISP will drop the session. Some routers see all those connections and intentionally drop the connection, as this looks the same as a PC which has a nasty virus and is part of the DDOS (distributed denial of service).

If someone is using torrent, they need to set it so it is less aggressive about the number of connections it starts. Or better yet, just don't let people do torrents.

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