 RadioDoc 58ef2c0 Premium,ExMod 2000-03 join:2000-05-11
·AT&T Midwest
1 edit | reply to BadtzMaru Re: Modem GUI w/ Router - ISO Definitive Answer
No I think I got it right the the first time. The issue is mostly one of what IP address the modem is handing out to the router's WAN port, and how your router handles having the same address segment(s) on each interface. Normally, the modem gives out 192.168.1.64/255.255.0.0, which is going to cause problems if 192.168.(0,1).x is on the LAN side of things and something gets an 192.168.1.64 or 192.168.0.1 address.
SO, try this...
•Let the modem do the PPPoE thing...
•Set the router to 192.168.2(or higher).1/255.255.255.0
•Set the WAN side of the router to "obtain address automatically" via DHCP, or to 168.192.1.64 (that's what it's going to get anyway)/255.255.0.0. If you set a static WAN side address be sure to enter DNS server info at the computers.
Sigh... That's what I get for answering the phone in the middle of posting.
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  BadtzMaru
join:2001-12-06 Cleveland, OH
| Funniest thing. I followed gdm 's advice. And it worked -- all this time, I'd been setting up my LAN to use 255.255.0.0 to try to get it to overlap with the subnet of my modem, which is actually attached to the WAN NIC of my router. How foolish! Setting the LAN subnet mask back to 255.255.255.0 did the trick. So, for anyone else who stumbles upon this, here's how everything needs to be set:
On the modem, all that needs to be changed from its defaults are the following items in Advanced>Connection Configuration page -- User ID and Password (of course), Connection Type: Connect on demand, and Connection Timeout: 0 [displayed as "Never"] -- the modem will need to be restarted after these changes:

On the router, use DHCP, IP address: 192.168.1.1 (although anything in 192.168.x.x should work), Subnet Mask: 255.255.255.0 (NOT 255.255.0.0). |
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  BadtzMaru
join:2001-12-06 Cleveland, OH
| reply to RadioDoc
said by RadioDoc :No I think I got it right the the first time. The issue is mostly one of what IP address the modem is handing out to the router's WAN port, and how your router handles having the same address segment(s) on each interface. But by default, the modem gives anything behind it a public IP address -- and this is a good thing since it avoids having to deal with double-NAT.
root@smoothwall~# ifconfig eth0 Link encap:Ethernet HWaddr 0?:?0:2?:16:?B:?9 inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:108914 errors:0 dropped:0 overruns:0 frame:0 TX packets:80639 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:86616849 (82.6 Mb) TX bytes:27983129 (26.6 Mb) Interrupt:9 Base address:0x8000
eth1 Link encap:Ethernet HWaddr 00:A0:CC:28:C5:09 inet addr:68.255.???.??? Bcast:68.255.???.??? Mask:255.255.255.0 UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1 RX packets:74586 errors:2 dropped:0 overruns:0 frame:0 TX packets:106498 errors:1 dropped:0 overruns:0 carrier:1 collisions:0 txqueuelen:1000 RX bytes:19365573 (18.4 Mb) TX bytes:86529362 (82.5 Mb) Interrupt:11 Base address:0xd800
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:127 errors:0 dropped:0 overruns:0 frame:0 TX packets:127 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:13051 (12.7 Kb) TX bytes:13051 (12.7 Kb) |
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  gdm Premium,MVM join:2001-06-15 Mchenry, IL clubs: | reply to BadtzMaru One thing under advanced---connection type set that to always attempt to connect on the modem. |
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  BadtzMaru
join:2001-12-06 Cleveland, OH | Got it. Interestingly, I had to reboot my router to apply the change network-wide. What's the advantage of "Always attempt to connect" vs. "Connect on demand" with a zero timeout? |
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 RadioDoc 58ef2c0 Premium,ExMod 2000-03 join:2000-05-11
·AT&T Midwest
| reply to BadtzMaru Yep. That's true. But it will still cause trouble if you try to overlap it's 192.168.0.x subnet regardless of what your router gets on it's WAN interface. That's how you get to the admin interface, and if your router thinks it's a LAN address it won't pass it to the modem.
Double-NAT isn't much of a problem on this modem since it passes everything through, sort of like a DMZ situation.
In any event, glad to hear you figured it out. |
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  gdm Premium,MVM join:2001-06-15 Mchenry, IL clubs: | reply to BadtzMaru always attempt to connect means it will be on 24/7 unless there is an outage, maintenance, etc.
Connect on demand means it will connect when you need the internet. |
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  BadtzMaru
join:2001-12-06 Cleveland, OH
| Seems like a fine line. On one hand, it will "always attempt to connect" regardless of what's going on on the inside, while on the other hand, it will attempt to connect (only) when it senses a packet directed to the outside world, and never disconnect. I guess the former is better if one's interested in obtaining an always on connection. |
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  gdm Premium,MVM join:2001-06-15 Mchenry, IL clubs: | Think of always attempt to connect like a bridge modem and having your router set to 'always attempt to connect'  |
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