UPC Scientific Atlanta confusion

craigcharlie

As title indicates, I have a Scientific Atlanta cable modem with UPC.

I've connected a Wireless router that I intend to use as an access point. I've turned off DHCP and set the IP address to 192.168.1.1.

I've connected two PCs so far, one via wireless and one via a wired connection - they both browse the web fine, that's great.

What I don't understand is, I can't seem to connect to the config pages of either the cable modem or my wireless router.

I've tried the gateway address, and all the usual suspects - e.g. 192.168.1.1, 192.168.100.1. Interestingly, the ip addresses of the two connected computers look like this:

79.97.w.x
79.97.y.z

I'm replaced the last digits with different letters to indicate that all the numbers are different.

Can anyone explain how to access the router OR modem?

An aside: my wifi-enabled phone (HTC) cannot successfully complete IP address assignment. it can see the router, but can't get an IP address. Any ideas how this is related? Never had a problem connecting when I used the router for DHCP.

Any advice is greatly appreciated!

best,
Charlie

Cable modems config page are generally 192.168.100.1

craigcharlie

Thanks Cisk, sorry that's what I meant to type before. I just edited the post to reflect that.

Also, just to add, before I added the router I was able to connect to
http://192.168.100.1/_aslvl.asp
but not to any other IP address for the modem.

from what i've read, I guess that means it was in bridge mode. I'm not sure why it was in bridge mode or how to turn bridge mode off.

The http://192.168.100.1/_aslvl.asp page also didn't really let me config anything. I used user/pass "admin/W2402", which it accepted, but then it didn't let me save the user access level. I think other users have experienced this as well.

jor el

It sounds like you've put the wireless router in bridge mode, so you've effectively disabled routing. The public IP on the WAN side is applied to the computers on the LAN side. UPC will give 2 (or possible 3) public IPs to each user, which is why you see two different public IPs assigned to the two computers.

You need to re-enable routing, and if you're going to disable the DHCP server on the router, then you need to set up static IPs on the computers that will connect to it.

craigcharlie

Thanks for the speedy and detailed response!

So any idea how I can take the modem out of bridge mode? I haven't been able to find info on this in the user guide or on google.

Re: your DHCP point - I thought that I had to disable DHCP on the router to use it as an access point. I got that from here: http://www.speedguide.net/articles/how-to-set-a-wireless-router-as-an-access-point-2556

Is that incorrect?

watty

You have a separate Router?

Is it an ethernet Router with 5th ethernet, the WAN port connected to Modem? (Reboot Modem if you change cable).

If it's a combo DSL Modem/Router you can't EVER use it as a standalone Router on a separate modem.

The Cable Modem *ONLY* bridges, it's just a modem not a router.

So either you have a DSL modem/Router and simply using it as a switch, which explains everything,
OR
you have a real standalone Router but you have plugged the Modem ethernet cable into a Switch port instead of special WAN 5th port
OR
you have a real standalone Router but you have somehow turned it into just a 5 port switch (bridged WAN and LAN ports).

watty

craigcharlie wrote: »

Re: your DHCP point - I thought that I had to disable DHCP on the router to use it as an access point.
Is that incorrect?

Incorrect

If you ALREADY have a a router (which the Scientific is not, it's just a modem, only one ethernet port?) and you ONLY want an Airpoint and Switch, then indeed you must disable the DHCP and other stuff so that it's not a Router. Because there already is a Router with DHCP.


If you need a Router to add onto a Modem, then normally you leave DHCP on, no matter if using WiFi or not. You can disable DHCP, but then nothing works at all. No Internet access unless you manually put a static IP of same subnet as router IP and the Router IP as Gateway IP.

The fact that you can browse internet at ALL with DHCP disabled means you are not using it as a router at all, but as Switch and Airpoint. Which is stupid and won't really work as the Scientific Atlanta is NOT a Router (at least most are not, esp. if only one socket).

WiFi and Router are two completely separate functions. You can get Routers with no WiFi. But the Scientific Atlanta cable Modems are usually just Modems. No Router. UPC does supply combo Modem/Routers, usually Cisco (actually Scientific Atlanta is Cisco).

craigcharlie

edit: I wrote this before you posted your second post - that's even more good info. thx. i just didn't get that the modem was not a router! I've never had cable before, only DSL with combo modems/routers.

So is my question below correct?

---

Thanks for the reply Watty. I'm learning slowly but surely here!

So from the three scenarios you outlined, i think this one applies to me:
"you have a DSL modem/Router and are simply using it as a switch"

So you said "you can't EVER use [a combo DSL Modem/Router] as a standalone Router on a separate modem." I THINK that clears stuff up for me....

So correct me if I'm wrong - What I need to do is get a standalone router and plug the cable modem's ethernet output into the WAN port?

I'm confused b/c the article I linked to in the previous post says "Do NOT use the Internet/WAN port on the wireless router to be used as an access point."


Thanks for any advice!

---

Just in case it adds helpful info, here's what's currently connected to the router:

- the cable modem, plugged into Lan 1
- the wireless router plugged into Lan 2
- a linksys pap2 VOIP adapter, plugged into Lan 3
- A wireless PC

All these items are working successfully. However, I can't access the router page and can't add a wireless connection for a wifi phone...

jor el

craigcharlie wrote: »

So any idea how I can take the modem out of bridge mode? I haven't been able to find info on this in the user guide or on google.

You don't take the modem out of bridge mode, just the router. The modem Ethernet output should connect to the WAN port on the router. You can disable the DHCP server on the router if you like, I've disabled it on mine. If you're using the router as an access point though, then it's no longer a router, and that's why you see the public IPs on the attached computers.

Why are you configuring it as an AP, and not a router?

I don't think you can access the Scientific Atlanta modem. There's nothing you can/need to change on it anyway, it's just a cable modem and UPC control all the settings. I have a similar setup (SA modem and Netgear router), and I've never accessed the SA modem. My Netgear router is at 192.168.1.1, and it get's a public IP on it's WAN side from the modem.

You may need to hard-reset the router, so it returns to default settings. I'm not sure what the procedure is there.

edit:

OK, you are using a DSL modem/router as your Wifi AP. This is not a good idea. Replace that with a router, one with an Ethernet WAN port.

craigcharlie wrote: »

I'm confused b/c the article I linked to in the previous post says "Do NOT use the Internet/WAN port on the wireless router to be used as an access point."

Ignore that article, you want to set up a Wifi router, not a wireless AP.

craigcharlie

Thanks Watty and Jor-el, I think I'm on the right track now.

From years of using DSL, I was just assuming that the cable modem was also a router.

I love how technology can make you feel like a complete newbie when you make mistaken basic assumptions. Classic, I feel like bambi in here.

So just to confirm, any bog standard wireless router with a WAN port should do the job I want, right? That is --- connect to the cable modem and route that IP to X number of wireless/wired connections on an internal subnet, with ports like like 192.168.1.x?

---

Ok I see I crossed posts again. I think I'm good to go, Jor-el said the same thing I did. thanks again Jor-el and Watty!!!

jor el

craigcharlie wrote: »

From years of using DSL, I was just assuming that the cable modem was also a router.

The move from DSL to cable or wireless often causes this confusion. With; why can't I just use my old DSL Wifi router on the new cable connection being the main sticking point. As you've found out, you can do this, but you really shouldn't. The DSL router is now operating as a simple Wifi switch, not a router. This means you can only connect as many computers or devices as the ISP gives you public IPs for. UPC do give 2 IPs, if not possibly 3, per customer. If you try to connect more devices then you'll drop currently connected devices.

Not having a router and NAT is also a security risk. It took me quite a while to get my head around all of this too, and I've also used two DSL modem/routers together when I really shouldn't have.

craigcharlie wrote: »

So just to confirm, any bog standard wireless router with a WAN port should do the job I want, right? That is --- connect to the cable modem and route that IP to X number of wireless/wired connections on an internal subnet, with ports like like 192.168.1.x?

---

Ok I see I crossed posts again. I think I'm good to go, Jor-el said the same thing I did. thanks again Jor-el and Watty!!!

That's it in a nutshell. Linksys WRT54G is probably the most highly recommended router going. Netgear make some decent ones too. Avoid Belkin like the proverbial plague.

watty

craigcharlie wrote: »

I'm confused b/c the article I linked to in the previous post says "Do NOT use the Internet/WAN port on the wireless router to be used as an access point."

We have two wifi points. One is the router and the other is a 2nd router set up as an Airpoint only, as per that article.

If for example you had a server room, you might put the router and its 4 port switch there and disable its wifi and use either a real Airpoint (a WiFi ethernet Bridge/Infrascture Base station) or a router that was spare (such as the now useless DSL modem/router) elsewhere, configured as only an airpoint.

I think now you have figured it all now. It is confusing. Especially since UPC actually does supply integrated modem/Routers too and more than one public IP. On ISPs that only do one Public IP, the wrong assumptions come to light quicker.

Since we have no phone line we have a UPS for the Outdoor radio link, Cable modem, 2 x DECT dual handset bases plugged into modem (two 061 numbers), Router + Wifi that has only one ethernet LAN port and 2 x 3Com Gigabit switches. The 2nd Airpoint at other end of house (phones and gadgets have poor WiFi range) is a Linksys WRT54G3G modified to be switch & airport only and with NiMH batteries and trickle charger added internally.