Member Avatar for Squires

Heres what I got:
Linksys WRT54G router
Seimans SPeedstream 4100 ADSL modem
SBC DSL ISP

Up until earlier this week I had a SS 5360 modem and it worked fine with my Linksys router, never had a problem. Then this week my modem dies. I get sent a new one from my ISP, a SS4100. Now my router cannot get an internet connection.

I can get an internet connection with my computer directly connected to the modem with the modem in PPPoE mode on the modem. I connect fine.

I add in the router, I set the modem to PPPoE on the PC(middle option) and set the router to connect through PPPoE, store my username and password and it will connects, but gives me the following:
IP:(dynamic address changes everytime I reconnect)
subnet mask:
default gateway:

When I connect to just the modem, I get a mask of

Any ideas why I am getting an incorrect mask and who is to blame for the problem(SBC or Linksys)?

OS: 2 comps, 1 with XP home, 1 with XP Pro
router firmware version: 1.00.6

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Generated

Short technical summary: seeing a WAN mask of 255.255.255.255 on the WRT54G while using PPPoE is expected — PPPoE is a point-to-point link and commonly shows as a /32 on the router’s WAN. That /32 does not prevent normal NAT for the LAN; a different mask (for example /24) will appear when the modem itself is doing PPPoE + DHCP/NAT to a directly connected PC.

Two practical, working layouts and what they mean:

  • Preferred setup (cleanest): make the SpeedStream act purely as an ADSL bridge and let the WRT54G run PPPoE and NAT. Configure the modem to bridge, disable its LAN DHCP if present, set the router WAN to PPPoE with the SBC credentials, and reboot devices in the order modem then router. The router’s WAN may still show 255.255.255.255 — normal.
  • Alternate setup (simpler if the modem won’t bridge): leave the modem handling PPPoE/NAT and set the Linksys WAN to obtain an IP (DHCP). Change the Linksys LAN to a different private subnet (for example 192.168.5.x as noted by ) to avoid IP conflicts. This works but creates double NAT and can complicate port forwarding.

Practical troubleshooting checklist:

  • Reboot modem and router (allow ADSL sync 1–2 minutes) to clear old PPP sessions.
  • If the ISP binds service to a MAC, enable WAN MAC clone on the WRT54G.
  • Verify PPP credentials and that only one PPPoE client is active on the line.
  • Update WRT54G firmware if the unit is old and PPPoE problems persist.
  • After changes, confirm the router’s WAN IP/gateway, ping a public IP (e.g., 8.8.8.8) to test routing, then test DNS name resolution.

Notes: ’s bridge-mode approach and ’s observation about the modem’s PPP options line up with the above. The /32 mask itself is a symptom of where PPPoE terminates, not a definitive error.

Recommended Answers

All 5 Replies

Member Avatar for marinme

I recently had an issue like this with one of my clients at work. Unfortunately, our solution was to replace the router. We were using the linksys wrt54g ver. 5 with the latest firmware and a westell 6100 modem through bellsouth though. But it sounds like it may be the same thing.

You may be able to use your existing hardware though. Can you configure the modem to handle PPPoE, handing out natted ips, then change the LAN ip scheme on the linksys to ? This may work for you.

Member Avatar for bmaguire36

You need to put your 4100 into "bridge mode" when running it with a router.
Type in the ip address of your speedstream 4100 into your brower, for the password use the code on the sticker on the bottom of the router. Select the bridge mode radio button and save. The 4100 will reboot and yoru will be back in business.

-Brian

Heres what I got:
Linksys WRT54G router
Seimans SPeedstream 4100 ADSL modem
SBC DSL ISP

Up until earlier this week I had a SS 5360 modem and it worked fine with my Linksys router, never had a problem. Then this week my modem dies. I get sent a new one from my ISP, a SS4100. Now my router cannot get an internet connection.

I can get an internet connection with my computer directly connected to the modem with the modem in PPPoE mode on the modem. I connect fine.

I add in the router, I set the modem to PPPoE on the PC(middle option) and set the router to connect through PPPoE, store my username and password and it will connects, but gives me the following:
IP:(dynamic address changes everytime I reconnect)
subnet mask:
default gateway:

When I connect to just the modem, I get a mask of

Any ideas why I am getting an incorrect mask and who is to blame for the problem(SBC or Linksys)?

OS: 2 comps, 1 with XP home, 1 with XP Pro
router firmware version: 1.00.6

Member Avatar for knsljo

You need to put your 4100 into "bridge mode" when running it with a router.
Type in the ip address of your speedstream 4100 into your brower, for the password use the code on the sticker on the bottom of the router. Select the bridge mode radio button and save. The 4100 will reboot and yoru will be back in business.

-Brian

Your quite right about bridge mode but i would normally put the router in bridge mode not the modem, i'm not familiar with this modem though most modems aren't configurable!:!:

Member Avatar for turtlebud

I have the 4100B, which I just got from att when I signed up for DSL. The bridge mode suggestion got me on the right track. You can configure the router's PPP mode. It's under the advanced options I think. The 3 options that i saw were "PPP on router", "PPP on computer", and bridged mode. The PPP on computer has a description which says something along the lines of the PPPoE is done on the computer or router. That's the one I picked and after the restart, it worked perfectly

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