[Machforr]

I recently built a dd-wrt router out of an x86 system.

eth0 connects to the modem and eth1 is connected to a switch that distributes the connection.
However, when my wife's computer logs on, my system loses the internet for several minutes (while hers works with no issues... which is good, otherwise I'd get an earful).

I can STILL access the router, mind you, but I can't seem to find the correct tweak to prevent my disconnection from happening.

I'm considering adding NICs to the x86 system instead of using a switch for more reliability, would that most likely solve this issue?

Thanks!

[Sp1derman]

No, that would not solve the issue. I have the same configuration and it's working fine.

Maybe an IP conflict? one PC is on DHCP, other PC has the same IP as manual setting?

[Machforr]

Both PCs are in DHCP. (As in "Obtain IP automatically")

If I try and set the NIC of either systems with a static IP they don't go online at all.

the dd-wrt router basic setup is set to "Automatic Configuration - DHCP".


Note that I'm not a full-fledged sysadmin. I'm already stretching my network config knowledge.
Thank you for giving me a hand

[Wildlion]

What are your settings on DD-WRT? Can you show us the config page? Most defaults should be fine, but just want to check..

[Sp1derman]

OK, "Automatic Configuration - DHCP" is the WAN Setup.

On that Page there is also the Network Setup.
Router IP is three times the same IP, the mostly used "/24" is netmask 255.255.255.0

DHCP settings, DHCP Server, Enable, max DHCP users maybe 10 or so.

Static IP Setting on the PCs is easy and that has to work.
put in an IP of your subnet (of course not the Router IP), netmask, Gateway and DNS is the Router IP

Save this and it should work.

Maybe you can post pics of your setup.
did you change anything in the standard Network and/or Advanced Routing settings?

[Machforr]

Ahhh. Seems putting the same ip 3 times is what did the trick for the static IP address to work.

I didn't touch the advanced menu... as I didn't want to break anything any further.

As always, it's something very simple but that is not easy when lacking knowledge
Thanks a lot guys, I really appreciate your help with this

[Machforr]

I cried victory too soon.

I eventually had to go back to getting IP automatically as neither systems would connect consistently after being given a static IP. It worked for a moment on one system, then would stop working the moment the other would log in and vice versa.

Neither system had the same IP, of course and a different IP than the router but within the same subnet, of course.

Here's the Basic config page:

[Sp1derman]

ok, we need more Infos

1. is the old DHCP (before you set up DD-WRT) disabled?
In your inital post you mentioned the modem. Maybe you use it also as DHCP-Server.

2. pls copy/paste (as Code) the Configuration Type under DD-WRT Status/WAN

3. if you use Windows-PCs, pls do "ipconfig /all" and copy/paste the infos from active LAN-Adapter from both PCs running at the same time.
Using Linux do ifconfig
We have to see IP, Gateway and DNS the PC gets from DHCP-Server

4. pls make pic from the rest of basic config page.

Normally a PC gets kicked out of Network if two PCs use the same IP and/or the same MAC-Address, so in your case maybe its the MAC.

[kernel-panic69]

You don't put the router IP in Gateway or Local DNS normally. That can tend to break things.

[Wildlion]

Gateway and Local DNS should be 0.0.0.0

does your modem do DHCP as well?

[Sp1derman]

@kernel-panic69 and @Wildlion

I'm confused, maybe I don't understand DD-WRT Networking.

If Gateway and Local DNS should be 0.0.0.0, how does DHCP-Server know the values to deliver to DHCP-Clients?

OR is that an DD-WRT internal handling, if in Gateway mode and if the WAN Port is active? And local DNS is active by enable "Use dnsmasq for DNS"?

[Machforr]

I'll try and be as thorough as possible:

Modem is a CBN8000. It has two LAN ports but while both work, only ONE is instructed to be used. If that modem has DHCP, it's not a very good one. All instructions require the use of a router to distribute the modem's signal. (It's not even WIFI!)

I don't have any other routers in my network, the DD-WRT x86 system 'router' is what should be doing all the work. My previous router doesn't work anymore.

Right now I have a switch that distributes the DD-WRT router's signal to all the systems and while it CAN be stable, my wife's system seems to suck all the connection (disconnecting my system!) for several minutes before things start to even out.

-= Here's the DD-WRT Status/WAN page:
WAN
Configuration Type
Connection Type Automatic Configuration - DHCP
Connection Uptime 10:01:57
IPv6 Address Disabled
IPv4 Address 198.91.168.105/27
Gateway 198.91.168.97
IPv4 DNS 0 209.197.128.2
IPv4 DNS 1 209.197.128.5
Remaining Lease Time 1 day 13:58:03

-= Here's my main system's ipconfig:
Windows IP Configuration

Host Name . . . . . . . . . . . . : DESKTOP-ACJ2SSD
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Mixed
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : [redacted: work-related]

Ethernet adapter Ethernet - Server:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
Physical Address. . . . . . . . . : 74-D0-2B-28-AA-23
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv4 Address. . . . . . . . . . . : 10.0.0.2(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet 2 - Web:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82579V Gigabit Network Connection
Physical Address. . . . . . . . . : 74-D0-2B-28-AA-EC
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::1697:3db8:6b3a:8fc%13(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.67(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Thursday, February 22, 2024 7:17:09 AM
Lease Expires . . . . . . . . . . : Friday, February 23, 2024 7:17:09 AM
Default Gateway . . . . . . . . . : fe80::210:18ff:fe8a:71cc%13
192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 141873195
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-28-06-6F-B9-74-D0-2B-28-AA-EC
DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled

-= The other system's ipconfig:
Windows IP Configuration

Host Name . . . . . . . . . . . . : DESKTOP-NHL09CE
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Mixed
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Ethernet Server:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82578DC Gigabit Network Connection
Physical Address. . . . . . . . . : 00-30-67-41-9B-4A
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv4 Address. . . . . . . . . . . : 10.0.0.3(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet 2 NET:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek PCIe GbE Family Controller
Physical Address. . . . . . . . . : 00-30-67-41-98-80
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv4 Address. . . . . . . . . . . : 192.168.1.78(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : February 22, 2024 7:17:17 AM
Lease Expires . . . . . . . . . . : February 23, 2024 7:17:16 AM
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet 6:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : TAP-NordVPN Windows Adapter V9
Physical Address. . . . . . . . . : 00-FF-81-7B-A5-8D
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

---=======---

I did check for duplicate MAC addresses but they are not the same.
I did reset the router values for Gateway and DNS, so the values shown are the default.

What I've been doing, however, is reset the router once both systems are up to rebalance the connection. Like I said, I still have access to the router even if my internet connection stops working, though I'd rather not have to do that all the time.

I hope this gives a better idea of what's happening.

Basic config page:

[Sp1derman]

I don't see anything wrong in your settings.

So this is try and error:
type in " ping 1.1.1.1 -t " and let it run all the time. check if it also disconnects if your wifes PC is powered on.

1. What you can try now is use another switch connected to eth1, hopefully you have another one.

2. Set Hostname same as Router Name and power on your wifes PC

3. enable IPv6 on second PC, DESKTOP-NHL09CE (you don't need to acticate IPv6 on DD WRT)

4. Disable SFE (Shortcut Forwarding Engine)

Maybe some other changes if all of this fails.

[Machforr]

Thanks for the suggestions, sorry for the late reply, I couldn't test earlier.

The ping command is really useful!

-= I did try a different switch, albeit a slower one, but the problem still occurs. Glad to know it's not the swith, though.

-= Not sure where to input the host name you are referring to in point 2.

-= IPv6 WAS enabled on DESKTOP-NHL09CE before. I noticed some strange DNS addresses in Hex and disabled it before posting last time.

-= I disabled SFE and saw no change.

Really starting to wonder if there isn't some BS happening on the modem side of thing, but I have no way of knowing.. I can't access the firmware of the thing.

Sorry about this headache.

[Sp1derman]

1. Hostname is under Basic Setup

2. Did you use Lan Port 1 of your modem?

3. As everything worked with your old router, I would point to the new DD WRT and not to the modem beeing the cause of the disconnects.

Try this:

4. disable the second NIC (the 10.0 network) on both PCs

5. Go to Security / Firewall and enable Firewall log, LogLevel high, enable Dropped and Rejected.
Open both logs, start the permanent ping an power on other PC.
When you see ping not working press refresh on outgoing log.

6. check also Status / Lan if both PCs are under Active Clients and DHCP Clients.

Maybe there is some Info for the reason of the disconnects.