More questions about RT31P2 behind existing router

Posts: 9 · New Forum Member Joined: May 01, 2005 Posts: 9

What is the most ideal way to set up my network with Vonage, based on the hardware I have below? Eventually I will be connecting from this network at home to my network at work via VPN, so I need to have this set up in a way that works well with that need. That is one reason why I thought I should have the Linksys on the lan side of the 3com router.

I was generally going for the "alternate" setup shown here http://vonage.com/help_knowledgeBase_article.php?article=88
but I have some questions related to this setup ...
- If I set it up exactly like that guide say (I'll have to reset the TA to default first) will I be able to access the TA config pages from my lan?
- Will I be able to connect another computer to the ethernet ports of the TA?
- Will the TA be on the same subnet as my router (192.168.1.X/255.255.255.0)?

My ISP is Brighthouse Networks (roadrunner), dynamic ip.

I have tried to configure my network generally as follows:

cable modem to 3Com officeconnect router (wired/wireless)
3com gets wan IP from RR via dhcp
3com assigns lan IPs via dhcp
The 3com is 192.168.1.1 (255.255.255.0)
3com out to a switch
switch also connects
--pc
--networked printer
--TA wan port (Lynksys RT31P2)
Lynksys dhcp off, lan ip static 192.168.1.10, wan ip ???
phone plugged into RT31P2 is working but I can't access the Linksys config pages from anywhere on the network with this setup.

No port forwarding, no dmz, no static routing, no mac address cloning.

Should I set it up where the Lynksys is on a different subnet 192.168.15.X ? I'm not sure how to do that and how to set the routers to work together, but that seems like it would complicate things so I was trying to keep everything on 192.168.1.X.

I'm pretty confused about it, but right now I have the flexibility to set it up any way I want. I want to get it going correctly, not just so that it works haphazardly.

Here's something I came across that sounds pretty strange:
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" have a Linksys (model # in sig) wireless router behind the RT31PT & mine works fine. I had trouble with mine until I used the RT31PT like a switch behind the wireless router. I will give you my setup to see if this type of setup will help you. Plug the modem ethernet to the WAN/INTERNET port of your wireless router & run all your wired pc's through the LAN ports of your wireless router (basically keep the router in front setup like you would without the RT31PT). What you do different is with the RT31PT. You take an ethernet cable & plug it in to the WAN/INTERNET port on the RT31PT & run the other end to one of the 3 LAN ports on the RT31PT then take another ethernet cable & run it from one of the LAN ports on the RT31PT to one of the LAN ports on your wireless router. This should fix it if your problem is a setup issue. If you already have this setup or a correct setup then it may be something else........
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Thanks for any help here ...

Posts: 51 · Posted: Mon May 02, 2005 12:14 pm Post subject:

I have an almost identical setup as yours and currently use VPN to connect to work. The only major difference is that I use a Linux box as the router where you have the 3com.

Note that I have the Linux box run a DHCP server and assign a fixed IP (192.168.0.20) to the RT31P2. This is essentially no different than setting it manually in the RT31P2 like you did.

When I first got the RT31P2 I hooked my PC up to one of the LAN ports and did some configuration via the admin webpages. One thing I did was to go to the Administration tab and enabled Remote Administration. I used port 8080. Now with my network configured in it's normal day-to-day setup (i.e. nothing hooked up to any of the RT31P2 LAN ports) I can access the RT31P2 at 192.168.0.20:8080.

Here are some details of my setup:

Ambit Cable Modem ----> Linux machine (nic1 - DHCP)
Linux machine (nic2 - 192.168.0.1) ----> Simple 8 port switch
Switch ----> several PCs (192.168.0.2 thru .6) and the RT31P2 (192.168.0.20)

Here are more of the details of my setup:

- RedHat 7.1 kernel 2.4.20-28.7
- Shorewall 1.4.10c
- I have QOS configured in the kernel via Shorewall. I am using HTB (hierarchical token buckets) which gives me complete control over the outgoing traffic.
- I am using the RT31P2 in a completely degenerate mode, i.e. just using it as a phone adaptor.
- I have my Linux box configured so that it is running a DHCP server and is supplying IPs to the PCs and the RT31P2. I have specifc IPs that are associated with the MAC addresses of the PCs and the RT31P2. I am confident I could configure the RT31P2 to have a static IP (and not get it's IP from the Linux box via DHCP) and make that work.
- I have a regular CAT5 cable running from my 8 port switch to the Internet (WAN) port on the RT31P2. This is the same kind of cable that runs from the switch to the PCs.
- I do NOT have ANY ports forwarded or treated in any special way on the Linux box for the benefit of the RT31P2. **** Any reasonable router that is doing connection tracking and can apply that to UDP traffic (e.g. iptables-1.2.8-8.72.3 in collaboration with the kernel) does NOT NEED PORTS forwarded. Forwarding ports will not hurt - it is just not needed. The RT31P2 constantly initiates a call home (that is why the led blinks about every ten seconds) to reestablish a connection. Look at /proc/net/ip_conntrack on your LInux box.

When I first got my RT31P2 I connected the WAN port to the hub and twiddled with the admin web pages to set it up and verify the MAC address. Once I had configured the RT31P2 I then setup the DHCP on the Linux box and power cycled the RT31P2. All is working well since.

Posts: 3 · Posted: Mon May 02, 2005 2:57 pm Post subject:

Hi vonage-user,

I'm using an almost identical setup to your's (and vtex's):

Motorola cable modem is plugged into WAN NIC of my Linux router (m0n0wall) and obtains IP via DHCP. LAN NIC of Linux router is plugged into a 3Com 24-port switch, and the router hands out IPs in the 192.168.10.x range via DHCP. Linksys RT31P2 Vonage router is plugged into the 3Com switch and has its WAN IP manually set at 192.168.10.253. Like vtex, I enabled remote administration and set the port to 8080, so I can access the admin pages at http://192.168.10.253:8080/. I left all of the other RT31P2 settings at their defaults (LAN IP, DHCP, etc.). I'm not using the built-in LAN ports of the RT31P2 at all; it simply acts as another device hanging off of my LAN.

I originally did not forward any ports on my Linux router to the RT31P2, but was running into the problem of calls going straight to voice mail. Outgoing calls worked just fine, but about 50% of the incoming calls would go straight to voice mail without ever ringing. I forwarded only the Voip ports on the Linux router to the RT31P2 and it has been rock solid ever since. I am also using the traffic shaping capabilities of the Linux router to give full bandwidth to Voip whenever it is active, and am not using the QOS of the RT31P2.

I had to set it up this way because I needed access to my home network while away and I am using the built-in PPTP server of my Linux router to do so.

Hope that helps.

Posts: 9 · New Forum Member Joined: May 01, 2005 Posts: 9

Thanks guys - it actually looks pretty straightforward then. I think my only problem may have been that I did not enable remote administration. I was assuming that I would be able to access the router config from the lan just by knowing the lan ip. I'll see if I can get that working.

So with a setup like that, can you use the ethernet ports on the linksys for another computer if you want to? I'm short on ethernet ports where this stuff is sitting and could use the extras.

What do I do with the WAN settings on the TA? Leave it on default (get from dhcp)? I'm confused as to whether the TA is getting an IP assigned to it's WAN side and the manually set static IP on the LAN side is different. Can you guys clarify what is happening on the WAN side of the TA with this config?

Thanks

Posts: 51 · Posted: Mon May 02, 2005 4:33 pm Post subject:

You can plug computers into the LAN side of your RT31P2. This makes things more "interesting" as far as robust service is concerned.

When you get back to being able to see your web-based admin pages in your RT31P2 you will see that the Setup page has "Internet Setup" and "Network Setup" sections. The former essentially influences how the router interacts with upstream packet flow (i.e. out of the RT31P2 WAN port). The latter are the downstream settings (i.e. the four Ethernet ports on the router). These settings are mostly independent. Normally you would get a DHCP supplied IP on the WAN side from the cable modem (ISP). You would set a non-public IP (e.g. 192.168.0.x) on the LAN side. Your setu is different because you are connecting the RT31P2 on a private LAN already.

The issues you need to sort out if you want to daisy chain the router AND hang PCs off of it are:
- you now need to worry about QOS in the RT31P2 AND any upstream routers
- you probably want your PC to be looking for the gateway at the 3com router
- you probably do not want the RT31P2 doing NAT or any other mangling of packets
- others?

I believe that the trick of looping the WAN port back to the LAN port (which is an alternative for this setup?) will make the RT31P2 look more like a hub and less like a router. I have not tried this - perhaps others who have can weigh in.

Posts: 9 · New Forum Member Joined: May 01, 2005 Posts: 9

OK - I am still a little confused but you managed to get me on the right track.

My main problem is that I was trying to configure the Linksys WAN IP and the LAN IP to both be 192.168.1.XXX and even had them as the same IP number sometimes. That was causing problems where remote admin wouldn't work, etc.

So I reset the TA and hooked my laptop to a LAN port, turned on remote admin, and then set the WAN ip to 192.168.1.10. I left the LAN settings as default, including the dhcp since I don't have anyhting attached to it right now anyway.

So now everything is working, including remote admin from my LAN and the phone attached to the TA sounds fine. So far so good.

I still don't really know how I could use those LAN ports on the TA since they are on 192.168.15.XXX but I'll figure that out later if I need to I guess.