Router conflict with switch

[Anthony5]

Just received a new Asus router DSL-AC52U and it turns out that 3 of the 4 LAN ports conflict with my Ethernet switch.

 

1-2-4 have time outs every few seconds, while port 3 hasn't. I have been testing for hours and it is always the same port that works.

 

If I connect direct to my PC, all ports work fine. I make use of the same cable to avoid confusions.

 

Is this an issue with my router ports, my switch, or something else?

 

Any suggestions how to fix this?

[Sandman77]

I have similar problem since a while connect is okay after 5 minutes it says no network access in Windows ,, but I not see any ip Conflict in Windows , looks like a overlapping of Ethernet Mac adress or unsorted or uncatigreized data channels without priority! But the time between a reconnect I got a no access error is always diffrent that's very strange


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[mtls2005]

I would suggest offering up a detailed description of your current networking configuration, from outside your home to your PC, and all that you have done so far to set it up and configure it.

 

With absolutely no information, my best guess is that the device between your new Asus router and the internet is confused, and doesn't know where to send packets.

[Anthony5]

50 minutes ago, mtls2005 said:

I would suggest offering up a detailed description of your current networking configuration, from outside your home to your PC, and all that you have done so far to set it up and configure it.

 

With absolutely no information, my best guess is that the device between your new Asus router and the internet is confused, and doesn't know where to send packets.

 

Not sure what you exactly mean with the setup from outside my home to my pc.

 

When I open a command dos and do a constant ping to my router it get a lot of time outs, but only on port 1-2 and 4 and when connected to the Ethernet switch.

 

In my router system log it shows that the LAN connection drops all the time.

 

I went to sleep around 4.40 am this morning, my router connected to my pc directly, and I put my pc to sleep.

 

I woke up around 9.30 this morning and this is the log I see. No LAN down, but a lot of activity while I was sleeping.

 

Can you please have a look and tell me what you see?

syslog.txt

[mtls2005]

Is this an issue with my router ports, my switch, or something else?

 

Yes.

 

Can you describe your network configuration? List all the devices you use, and how you've configured them.

 

 

[Anthony5]

7 minutes ago, mtls2005 said:

Is this an issue with my router ports, my switch, or something else?

 

Yes.

 

Can you describe your network configuration? List all the devices you use, and how you've configured them.

 

 

 

 

The system log I uploaded is my PC and my router, nothing else connected.I see a lot of activity in that log, even while the PC was sleeping.

 

What do you see in that log?

 

When I have the issue where the LAN is dropping out, system log says every 2 seconds lan down ; lan up my configuration is a s follow.

 

Network switch 16 port. Only active devices connected are another router from which DHCP is disabled en a few ip cameras.

 

I will now disconnect the cameras, and report back in a few minutes.

[Anthony5]

I have now disconnected every thing from the Ethernet switch, only my PC and my modem/router are connected to it.

 

Included are 2 system logs from my router, one with LAN 4 connected to the switch, and the other with LAN 3 connected to the switch.

 

To be clear, my PC is connected to one port on the switch, while my router is connected to another port on the switch.

 

 

syslogLAN3.txt

syslogLAN4.txt

[thedemon]

Have you tried a few different LAN cables? Even though the same cable has no problem on one port but does on another, I would still suspect the cable first.

[Anthony5]

yes tried 3 different cables, including the one that came with the router.

[Anthony5]

Ok next test. I connect LAN 4 from the router to the PC, and connect LAN 2 from the router to the network switch.

 

This is the system log.What can you conclude?

 

 

syslogLan2+4.txt

[thedemon]

Do you have another switch you can substitute to see if the problem goes away?

 

I have seen incompatibilities between switches and devices before, particularly when both are gigabit.

 

Another thing you might check is whether the problem ports are connecting at 1000 mbps or 100. Does the switch have different coloured link lights depending on connection speed? 

[thedemon]

Also, if you can confirm that your PC is connecting to the switch at 1000 mbps and has the time-outs, try forcing your PC to connect at 100 mbps to see if the problem goes away.

 

That wouldn't be a solution but would help to narrow down the culprit.

[Anthony5]

Last test. LAN 2 is connected to the PC, while LAN1 and LAN3 are connected to the switch. Nothing else is connected to the switch or the router.

 

This should definitely give a clue to the experts, which I'm obviously not.

 

I notice that I now receive packages with own address as source on LAN 1 and 3. So there is a conflict with my switch.

 

Point is I bought the router from Lazada yesterday. I can return it, but if they find no fault they of course will not refund me.

 

So where is the issue, with my router or with my network switch?

 

Edit: the router is Gigabit while the switch is 100Mb, the Ethernet adapter in my PC is also Gigabit.

 

How do I check at what speed it connects, or how do i disable that it connects at 1000 Mb as that will probably will be the cause of the conflict since there are no conflicts between router and PC

 

 

syslogLan2+1+3.txt

[thedemon]

Sorry I had assumed the switch was gigabit. Since it isn't gigabit so it can only connect at 100 mbps so there is nothing to check except that it really is connecting at 100 and not 10 (can happen).

 

You can check the connection speed in the "network and sharing center" then click on "connections". That will show the link speed.

 

If you suspect the ASUS is faulty but have problems with Lazada, the ASUS service centre will replace it (from my experience) no questions asked.

 

Personally I would replace the switch anyway. Gigabit switches are cheap now.

[Anthony5]

2 minutes ago, thedemon said:

Sorry I had assumed the switch was gigabit. Since it isn't gigabit so it can only connect at 100 mbps so there is nothing to check except that it really is connecting at 100 and not 10 (can happen).

 

You can check the connection speed in the "network and sharing center" then click on "connections". That will show the link speed.

 

If you suspect the ASUS is faulty but have problems with Lazada, the ASUS service centre will replace it (from my experience) no questions asked.

 

Personally I would replace the switch anyway. Gigabit switches are cheap now.

 

 

I hear you, but bought the switch just 3 months ago.

 

I probably gonna get a replacement if I pursue it, but it makes no sense of course replacing the router if the issue is elsewhere.

[Anthony5]

51 minutes ago, Anthony5 said:

Last test. LAN 2 is connected to the PC, while LAN1 and LAN3 are connected to the switch. Nothing else is connected to the switch or the router.

 

This should definitely give a clue to the experts, which I'm obviously not.

 

I notice that I now receive packages with own address as source on LAN 1 and 3. So there is a conflict with my switch.

 

Point is I bought the router from Lazada yesterday. I can return it, but if they find no fault they of course will not refund me.

 

So where is the issue, with my router or with my network switch?

 

Edit: the router is Gigabit while the switch is 100Mb, the Ethernet adapter in my PC is also Gigabit.

 

How do I check at what speed it connects, or how do i disable that it connects at 1000 Mb as that will probably will be the cause of the conflict since there are no conflicts between router and PC

 

 

syslogLan2+1+3.txt

 

I notice from the log included in above post that it is only port1 that goes down all the time.

 

This confirms that port3 has no issues with the switch, while the other ports have.

 

How are the odds that a replacement router will solve the problem?

[mtls2005]

Personally I would take the switch out of the network and test your new ASUS DSL modem/router with a PC connected to each of the 4 ethernet ports in succession.

 

IF all 4 ports work then I would connect port #1 on the Asus to the UPLINK port on the switch, and est the ethernet ports on the switch.

 

I guess there could be some issue with the new Asus unit, or the old switch? Did this old switch work previously in a similar configuration? 

 

I might noodle through the Asus UI to see if there is a user-selectable setting to configure an uplink port.

 

 

What is the make and model of the "network switch"?

 

Typically ethernet ports are auto-sensing so there really shouldn't be any issues mixing 10/100/1000.

 

 

 

 

 

[Anthony5]

6 minutes ago, mtls2005 said:

Personally I would take the switch out of the network and test your new ASUS DSL modem/router with a PC connected to each of the 4 ethernet ports in succession.

 

IF all 4 ports work then I would connect port #1 on the Asus to the UPLINK port on the switch, and est the ethernet ports on the switch.

 

I guess there could be some issue with the new Asus unit, or the old switch? Did this old switch work previously in a similar configuration? 

 

I might noodle through the Asus UI to see if there is a user-selectable setting to configure an uplink port.

 

 

What is the make and model of the "network switch"?

 

Typically ethernet ports are auto-sensing so there really shouldn't be any issues mixing 10/100/1000.

 

 

 

 

 

Switch is D-link DES-1016D

 

What you suggest I have been testing for the past 12 hours.

 

LAN ports on router connected to PC all work without issues.

 

LAN ports from router connected to the switch, and PC connected to the switch, only port 3 from the router works properly. The other 3 ports drop out every few seconds.

 

Router interface is very sluggish when one of those 3 ports connected to the switch

[Anthony5]

What does a line like the one below mean in the router system log?

 

kernel: DROP IN=ppp0 OUT= MAC= SRC=95.90.213.91 DST=180.183.5.248 LEN=129 TOS=0x00 PREC=0x00 TTL=46 ID=58998 DF PROTO=UDP SPT=47733 DPT=6881 LEN=109  2016-09-09 11:20:23

[Anthony5]

One more update.

 

I have a decade old TP-Link switch laying around, which is obvious 10/100Mb

 

I connect port #4 of router and PC to that switch. No issues other then the warnings similar to the one in above post, which I still have no clue what they mean.

 

No LAN drops or whatever.

 

I change the same connections to the D-Link switch and straight away the LAN drops are there again.

 

So 100% sure now it is a conflict between router and D-link switch.

 

Remarkable is that there is NO issue if I use port #3 from the router.

 

So what will be the odds that the problem will be solved with a replacement router?

[mtls2005]

Maybe a port scan?

 

Asked again, for the last time:  Did this old switch work previously in a similar configuration? 

 

And you are using the Uplink port on the D-Link switch? Using a "straight" (not a cross-over") ethernet cable?

 

OK, hard to keep up...can you use your "old" ADSL modem/router to see if that works with either/both switches?

 

My best guess is that your new Asus ADSL modem/router is working properly, and that an exact replacement will not address your issue. 

 

Maybe see if there are any firmware updates for the Asus device.

[Anthony5]

2 minutes ago, mtls2005 said:

Maybe a port scan?

 

Asked again, for the last time:  Did this old switch work previously in a similar configuration? 

 

And you are using the Uplink port on the D-Link switch? Using a "straight" (not a cross-over") ethernet cable?

 

Yes the switch owrked properly previously and still work properly with other routers.

 

There is no uplink port on the Dlink switch, and yes I use straight LAN cables.

[mtls2005]

OK, the manual shows an uplink port, but maybe port 1 is the uplink port on your version?

[mtls2005]

Go into the Asus UI, Advanced Settings>LAN>Route

 

Is Enable Static Routes set to Yes, or No?

 

If Yes, what are the listings under Static Route List?

 

[Anthony5]

40 minutes ago, mtls2005 said:

OK, the manual shows an uplink port, but maybe port 1 is the uplink port on your version?

 

 

Great, my switch doesn't have an UpLink port and in the manual also doesn't show anything about port #1 being the UpLink.

 

But I have tested it with port #1 used as UpLink, and it solved the issue. I can now connect either port from the router to the port #1 of the switch, and there are no LAN downs anymore.

 

Thanks for the help, much appreciated.

 

Now if you only could figure out the meaning of those multiple warnings as posted above

 

Static route is not enabled in the router but is it advisable to enable it?

[Anthony5]

The error warnings are indeed port scans, and come from all over the world.

 

Anything I can do about?

[Anthony5]

I celebrated too early.

 

Lan still drops occasionally, but now only once every 15 minutes or so.

 

Should I replace the router or not?

[KittenKong]

3 hours ago, Anthony5 said:

..... LAN1 and LAN3 are connected to the switch.

 

This is wrong. There should only be one connection between the switch and the router.

 

I suppose that you have tried turning everything off and then restarting it all in the correct order? The correct order being: router, switch, devices.

[thedemon]

1 hour ago, Anthony5 said:

I celebrated too early.

 

Lan still drops occasionally, but now only once every 15 minutes or so.

 

Should I replace the router or not?

 

You mentioned in an earlier post that you swapped the switch and there were no issues. Therefore I think the chances are very high that replacing the router is going to yield the same result unless you get a different model router and then who knows.....

 

I think you need to change the switch.

 

Or a cheaper solution would be to buy a small (5 port) gigabit switch to connect your router and PC and then connect that to the DLink switch for all the cameras etc. Cost would be a few hundred Baht.

[JetsetBkk]

A diagram of your network would be really useful