Help Needed with Router Instability

I've been struggling with router stability quite a bit. I suspect that I'm doing something wrong with the configuration. I'm sharing a single DSL line for my entire home network, using DLink DSL500T DSL Modem/1-port Router. The sharing is done via DLink DI724P+ router with Wifi AP & 4-port 100/10 Ethernet. Both DSL500 & DI724P is capable of connecting to ISP via PPPoE, though the DI724 lacks the phonejack so cannot be wired directly and must be routed through the modem. I'm configuring DSL500T to provide Internet gateway, enabling both its NAT and DHCP functions. While the WiFi router is used exclusively to provide WiFi Access Point and 100BaseTX connection to one or two PCs. The followings shows connection map.

ISP -----> DSL500T -------> DI724P -----100BaseTX----> PCs | |-------- WiFi -------> Notebooks

DI724P is functioning as hub for all equipments and the DI724P WAN port is currently not in use. DHCP function on DI724P is disabled. I've tried to disable DSL500T's DHCP function, using DI724P to dynamically assign IP instead. This doesn't seem to work at all.

One thing I have not tried is to set DSL500T in bridge mode and to use DI724P both as hub and router for IP traffic. The problem with this is that I'm not sure what setup I should be using for DSL500T in bridge mode.

My problem right now is that sometimes the Internet just stops working after any length of time between 24 to 48 hours. Upon rebooting the hub, the Internet starts working fine again. I have a nagging feeling that I'm just not setting something right. Any thoughts? TIA


Reply to
K. Laisathit
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I believe your intermittent problems relate to improper TCP/IP properties regarding DNS config.

Make sure only your outer border router (connected to the phone line) forwards to your ISP provided DNS server.

Make sure all your internal machines/devices point ONLY to your internal DNS and forward unresolved requests to your outer border router. Specifically, do not assign your ISP provided external DNS IP to your inside clients.


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I'm trying to translate your suggestion into actual config. So, here is roughly what I'm doing.

  1. Enable DHCP on the DSL modem
  2. Disable DHCP on the WiFi hub
  3. Set WAN on the WiFi hub to static IP, pointing internal IP of the DSL modem [I'm suspecting that this is irrelevant]
  4. Set every machine to obtain DNS dynamically

Compared with:

  1. Disable DHCP on both networking devices
  2. Assign IP of all networked devices manually, by 2a. Setting Default Gateway to DSL modem IP 2b. Setting Primary DNS to DSL modem IP

Any thoughts? Thanks.


Reply to
K. Laisathit

Do you have a dummy static private IP in an unused network assigned to unused DI724 WAN (maybe it is attempting to connect its WAN)? I had a somewhat similar problem when I dumbed down an SMC 7004AWBR to act as a switch and wireless AP. Although, my problem was just intermittant 5-10 second delays due to interrupted arp response through the SMC.

When I had the WAN of the SMC connected to my main router, I had no such delays. But then the LAN side of my SMC had to be a different network.

Not sure why another post says not to use your ISP's nameservers. I would think that your ISP's nameservers would be more reliable. But then I do my own caching DNS (in Linux, with zones added for my LAN), because when I first got SBC adsl years ago, their nameservers were sluggish.

Reply to
David Efflandt

PS: One other thought is that the LAN2LAN connection between the DSL500T and DI724P should likely be a crossover cable, if not an uplink port. Many stand alone switches are auto sensing for cable type, but not sure about the LAN switch ports in modems/routers.

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