ZyXEL → Configuring your ZyXEL 645M as a router.

Hi ya'll

I was having problems connecting more than one computer this DSL Modem/Router and was unable to find any help with a simple google search, so I thought I'd post a quick how-to here to help anyone else out.
The ZyXEL I got came preconfigured from sprint as a router, but the Subnet mask was set to 255.255.255.252 by default which limits the range of IP addresses the router will talk to to just 2 (192.168.1.1->the ZyXEL router and 192.168.1.2->1 client computer). When you try to change the subnet mask something more reasonable like 255.255.255.0 an error message pops up informing you that you are not allowed to change it. So here's how to fix the problem:

1. Go to "start" and click "run"
2. Type in "command" and hit "enter" to bring up a command prompt.
3. Be sure to logout of the last web administrator connection you had to the router.
4. Type "telnet 192.168.1.1" to telnet into the router.
5. You will be prompted for a password. Enter the administrative password (1234 by default).
6. You will get a menu with several numbered choices. Type "24" and press enter to bring up the system maintenance menu.
7. Another menu will appear. Type "8" and enter to bring up the command interpreter mode.
8. you will get a command propmt (probably "Sprint>_") with a blinking cursor after it. Type "sys multiuser on" and press enter
9. the router should say "OK" below where you typed the command and you should get another command propmt. Type "sys multiuser status" and press enter. The router will return "On" below the prompt to let you know that multiuser mode is on. You will get another command prompt.
10. type "exit" at the prompt and press enter to exit the command interpreter mode.
11. type "99" and press enter to close the telnet connection to the router.
12. Type "exit" and press enter to exit the command prompt.
13. Open your web browser and connect to 192.168.1.1 to open the web administrator. Log in using admin and the administrative password.
14. Click "Advanced Setup" on the left hand side of the screen.
15. Click "LAN" on the left hand side of the screen.
16. Change the subnet mask under The TCP/IP section to something more reasonable (like "255.255.255.0"). And click apply.

Your router will now talk to any device on the network with an address of 192.168.1.XXX where XXX is any number between 1 and 254. You will probably want to change the DHCP pool number to something more reasonable (like 50) after you change the subnet mask, but you will have to change the subnet mask first and apply the changes before you are able to do so.
And that's it. Congratulations. You just saved yourself 30 bucks and a trip to Best Buy. You can plug the ZyXEL router straight into a hub or switch (remember to use a regular ethernet cable and not the sprint provided cross over cable) and you should be able to connect to the internet with any device configured to use DCHP. If something doesn't work right, invite your favorite computer nerd over, offer him beer of (if your of the female persuasion) something even more tantalizing and show him this how-to. He should be able to figure out what's going on, and if not, you should keep the beer.

Nathan

turdburglar2:

Is there any documentation for this command? Does it enable routing and disable DSL endpoint functionality, or just switch something else?

I've got a 645ME+ here and I've love to see if that works, but don't want to take any unnecessary risks.

Thanks

HogWild

You have one clue indicating this applies to a Sprint-supplied P645M. The Earthlink (and I believe Covad) supplied P645M-11 running firmware 2.50(EK.x) does not recognize the "sys multiuser" CI command nor does it have any form of web interface. Earthlink also supplied P645(M?)-UHP models that do have a web interface and this *may* apply - except AFAIK no one has ever discovered the password (P645M-11 password was "mspgzyx").

Moral: There's MANY customized versions of the "P645M" so everyone may see totally different things.

I didn't find any actual documentation for the command. My 645m actually came configured as a NAT router, just with a subnet (255.255.255.252) that only allowed it to see one other IP address. Turning multiuser on just allows you to change the subnet mask to something bigger. Using the switch "off" instead of "on" will turn the multiuser mode back off again.
I'm not sure how your network is configured, but according to the sprint guy on the phone (who told me that this was not really a router and that I would need to buy a router if I wanted to hook up more than 1 computer) these "boxes" can be put into bridging mode, where you have to hook a PPoE client (like a linksys, netgear etc router or a computer configured with PPoE software) up to the ethernet port on the back. You could also plug a secondary (linkys, etc.) router in with the default configuration on the ZyXEL and set the secondary router to use the internal address the ZyXEL provides (192.168.1.2) as the "WAN" address which would form a double NAT network which is really just completely silly (and pretty frustrating if you want to set up port forwarding for some reason).

Hope this helps clear things up a little.

I'm actually not sure who technically is my provider. I signed up with sprint and I'll be paying my bills to sprint, but the login for the PPPoE is actually a xxxxxx@earthlink.net login. The most specific model number I an find on this thing is "645M-plus ADSL Modem-Bridge" and the ZyNOS f/w version is 2.50(CG.3). The header when I telnet in calls it a 645ME+.
The default password on mine was "1234". In the html instrunction file provided by Sprint, the password was given with instructions to change it. There's even a security advisory out about the default password. »www.wired.com/news/infos ··· ,00.html

I'd be willing to bet that most of these models are all the same hardware and very very similar software, just with different features enabled by default (different sw features). There are some commands on my router that look interesting (sys mode, sys enhanced, sys model ) but that tell me that "The command is not supported in tis mode". These sound kind of like cisco's permision modes if I remember right. Getting a web interface or telnet interface is probably just a matter of getting the password (no small task) and enabling them.

Nathan

ZyNOS version: V2.50(GC.3) | 11/29/2002
romRasSize: 1136740
system up time: 27:54:56 (9957f1 ticks)
bootbase version: V2.09 | 9/26/2002
ZyNOS CODE: P645ME+ ATU-R Nov 29 2002 13:40:14
RomFile Checksum : 2ce3

P.S. I just found this on the ZyXEL web page. Might not work with every model, but it's probably worth a shot:
9. What should I do if I forget the system password?

In case you forget the system password, you can erase the current configuration and restore factory defaults in three way.

1. Use the Web Configurator.
2. Use the RESET button on the rear panel of Prestige 650 to reset the router. After the router is reset, the LAN IP address and the SMT password will be reset to '192.168.1.1' and '1234'. So now you can reach the router through console port or telnet again.
3. Upload the default ROMFILE via console port to reset the SMT to factory default. After uploading ROMFILE, the default system password is '1234'.

Thanks, this is excellent information to know. I've only had
DSL a couple of weeks [had cable before], and I didn't know
the first thing about it, although I had experience way back
with ISDN and Zyxel modems. 'New ballgame here !
I accessed my 645M and looked around, and did notice that 255.255.255.252 mask; I tried changing it and got the same error. Anyway, I had a router/firewall I wanted to install;
I tried my Snapgear first and had no luck. I tried a Linksys
BEFSX41 and "instant connection". I played with the Snapgear
for a while before finally figuring out how to get things up and running. I configured it with an IP of 192.168.1.2, and set up the DHCP server to hand out addresses in this range.
Again, good info. Thanks.

I recently discovered this fun and exciting link. It at least fot me into the configuration if you are having problems with that.

»Covad + ZyXEL 600 series 645 modem NOT router

I found that you can also just update the firmware on the 645ME-A1 with the firmware for the 645R-A1 (link to 645R-A1 below) and presto chango you get a 645R-A1 box. Both pieces of hardware use the same chipsets just different firmware code.

»ftp://ftp.zyxel.com/P645R-A1/f ··· dard.zip