Topic: Can I use two ISP with SME?

[Lazo]

Don't kill me for asking this!! I just want to know if this can be achived!! I got two ISP accounts, one is a DSL, and the other is an ISDN line, my question is, can I use the DSL to provide Internet to my LAN, and I want to use the ISDN for VPN, webmail, webserver and any remote access to the server, why do I want it this way? because my DSL provider gives me an local IP (10.xx.xx.xx), and is behind a firewall, so I can not access my server for outside the LAN (Internet), but my ISDN link gave me a real IP (dynamic, but with dnsalias is almost like static). I wanto to use the DSL because is a 512/256 Kbps, and is a way better browse experience than with ISDN (128 kbps with bounding).

Any help will be really appreciated!!

Thanks!!

[Chris O'Donovan]

I'd say that the simplest solution would be to get two of those $US99 cable/DSL router boxes and put one on your ISDN line and the other on the DSL line. Then have a DMZ subnet with the two routers and the external interface of your SME box.

Configure the router on the ISDN line to forward port 80, 22, 25, etc to your SME server, and not to provide DHCP. Make sure it has a different DMZ IP address than the DSL router.

Configure the router on the DSL line to provide DHCP.

Configure the SME box to use DHCP to get it's external address, routing info, etc (which will come from the DSL router).


Make sure that the routers that you get are configurable with a text browser or telnet. I know that the NetGear brand routers can be configured with a telnet client. One brand (I forget which) requires a javascript enabled browser.

I, of course, haven't tried this...

Chris

[Boris]

It may not work.
You need to specify default gateway (lets say DSL router)
If packet comes to SME from ISDN, reply will try to go via DSL (as a default gateway) via different IP. I only see the use of it if you know list of the networks(hosts) connecting to second line, then you can manualy specify routes to those networks via this (ISDN) gateway.

[Lazo]

Thanks for your replay!!

[Chris O'Donovan]

If the router connected to the ISDN line is doing NAT, won't any reply from the SME server to incoming packets go to this router?

Chris

[Lazo]

if my dsl modem/router is my default gateway, I think all the traffic that goes to the Internet goes here (my DSL is firewall by my ISP, and it gives me a private IP), my question is, If some access (thru my ISDN) my SME server (like VPN, webmail), I think he can reach the server, but when the server replays, what happens??? If the replay goes to my default gateway? or thru my isdn (maybe not), if It goes thru my DSL, can a two way communication can be established??


DSL (private IP) is firewalled by the ISP, but ISDN don't..

ISDN/freesco                     DSL/router
       |                                       |
       -----------------HUB----------------
                           |
                        SME
                           |
               PC-----HUB-----PC
                        |      |
                      PC   PC

Both freesco and the DSL router can be configured to be NAT, and freesco can be configured an ethernet router

Or there is another way to to this!!

Thanks!!

[Boris]

On the second though about Chris O'Donovan’s idea, it may work, but SME server should not be your server-gateway. Configure it as a “server only” with gateway address of your ISDN router. Connect to the same hub as workstations. Workstations will use DSL as Internet connection, but SME will use ISDN.
Something like this

ISDN/freesco192.168.0.2   DSL/router192.168.0.1
|                     |
-----------------HUB----------192.168.0.0
|                            |          |        |
PC192.168.0.100    PC    PC     SME 192.168.0.3              

Gateway for PC will be 192.168.0.2, for SME 192.168.0.1

[Boris]

Sorry, correction
Gateway for PC will be 192.168.0.1, for SME 192.168.0.2

[Chris O'Donovan]

I still like my idea better.

The DSL router is the default gateway for the SME external interface, but if the request comes via the ISDN router the replies will go to the ISDN router because it is on the local (DMZ) subnet, not via the default gateway (ie, the DSL router).

Chris

Apologies for ASCII art...

 --- internet--
 |            |
ISDN         DSL
 |            |
router1    router2
 |            |
 ----  --------
    |  |
   DMZ hub (192.168.1.x)
     |
  SME server
     |
 internal hub (192.168.2.x)
 |    |    |
PC1  PC2  PC3 ...