Question How does an Asus router AC88U decide a device is "offline".

[MungersMike]

On my LAN the Asus router shows many active devices as "offline" in the Network Map displayed by the Web router UI and by the ASUS Router app.

 

[jsmithepa]

Assuming this is from the DHCP server, clients did no reply from the last RENEW interval, but DHCP retains old IP as long as it can fulfill new requests.

 

[MungersMike]

The DHCP lease list is correct, showing all the devices I know about. But the Network Map shows half of these as "offline". So I conclude that the router wants something else beyond an active lease to list a device as "online", but I cannot figure out what it is. My best theory is that this is simply bug, as earlier ASUS routers do not show this behavior.

 

[jsmithepa]

So I conclude that the router wants something else beyond an active lease to list a device as "online", but I cannot figure out what it is.

Why would you make that conclusion? My guess is you are reading this ONLINE literally as "ready to go, able to access Internet, can go endpoint-to-endpoint." All the DHCP cares about is a client responded, seems to be alive" but the rest of it, it doesn't analyze the data stream and go "a-ha, is talking to Google" that's not its job nor a run-of-the mill home router has such capability, you are giving it too much credit.

 

[MungersMike]

I think I understand what the existence of a DHCP lease means. And, indeed, the lease table lists all the devices in my house that are powered up and either connected to the ethernet LAN or connected to the WiFi. And the leases are being renewed each day All that seems normal. What I do not understand is why only about half of these are shown in the Network Map as "online." The others are lists as "offline" and the IP address that is shown in the DHCP lease table is blanked out in the Network Map. This is true for both the map shown by the router's web interface and the map shown by the ASUS ROUTER app on my iPhone. Devices will remain "offline" even when they are active, e.g. , the printer is printing while remaining "offline".

 

[jsmithepa]

the printer is printing while remaining "offline".

^This doesn't make sense. Gotta be a bug. Ask ASUS.

 

[MungersMike]

I think it is a bug too. I posted to see if anyone else sees this behavior on their ASUS router. My previous router, a N66U, did not behave this way.

 

[jsmithepa]

Configure lease time to say 2 hours see if that works better for you.

 

[dspit1664]

I would agree this seems a certain defect.
No router should do this.

 

[jsmithepa]

Another possibility is the MAC is been age out from the ARP table, the printer keeps printing 'cuz all the data is already in its buffer.

 

[dspit1664]

I guess my query is basic - Why would the router say devices are offline when they are plainly not ?
Other routers I’ve used have never done this so why does the Asus AC38U ?

Surely being DHCP - I shortened the lease to 1 day and still all systems which were showing offline still showing as offline.

 

[bill001g]

You could load the merlin firmware. The asus-wrt is outdated but merlin is based on it. Maybe if works different.

Key here is if you REALLY want to know what the means you can look at the source code. The factory firmware has many of the features from the merlin image so it likely work the same so you could dig though the code and see what factor is used.

 

[dspit1664]

Perhaps I could reduce the subnet size to such that it would have to re-use the ip addresses ?

 

[dspit1664]

You could load the merlin firmware. The asus-wrt is outdated but merlin is based on it. Maybe if works different.

Key here is if you REALLY want to know what the means you can look at the source code. The factory firmware has many of the features from the merlin image so it likely work the same so you could dig though the code and see what factor is used.

I only have a dsl-ac68u can I load merlin on to it ?
ASUs is new to me so not sure

 

[jsmithepa]

I guess my query is basic - Why would the router say devices are offline when they are plainly not ?

As Bill Clinton famously asked, it depends what do you mean by the word "is" is.

There will be several definitions of ONLINE, according to whoever vendor you talk to.

This still bothers u after all this time?

 

[dspit1664]

For me, forgot to mention:

1. Just got my router
2. Not used ASUS before
3. I’m trying to find via google - why devices are showing offline and others not when all devices ‘are’ online. Never had this with other routers.

Are you/we saying it’s due to device vendor configs and how they react to alive status messages from the ASUS router. ?
So yes I’m still concerned as an app which proports to allow - monitoring/maintenance/status checking of devices connecting to it poor showing. Does this not ‘have to be’ a defect in router ?
There seems to be very little out there to help. Am I wrong ?

 

[bill001g]

My mistake I didn't realize this was a old thread with a new post on a different router. DSL routers tend to not have third party firmware. The asuswrt used to run on some of them but they stopped updating it and it has a couple security exposures....that is kinda where the merlin image got started.

BUT if you really want to know why it function the way it does the source code is still a valid option. The DSL part it in a completely different area. I just am not ambitious enough to do the leg work for you.

 

[dspit1664]

Aha my mistake also I should have been a lot clearer or created a new thread. I was/am looking for help on this very issue however as we now know on a diff router.
Thanks for responding 👍

on last query - find it odd that asus don’t have their own official forum is there some history / reason for this ?