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Resolving Hostnames

Discussion in 'Asuswrt-Merlin' started by logicalmind, May 29, 2020.

  1. logicalmind

    logicalmind New Around Here

    Joined:
    May 26, 2020
    Messages:
    3
    I have a lot of devices connected to my RT-AC68U router. To the point where I ran out of room for entering static dhcp assignments in the UI. I switched to the dnsmasq.conf.add method. One of the problems I have is with the resolution of hostnames in the UI. After scouring the forums I see that this limitation is due to the asus-provided networkmap binary. But I'm wondering if there is any kind of workaround. Maybe maintaining a cross-reference in the hosts file or something. Or maybe I messed something up, but I don't think I did.

    One example. In my dnsmasq.conf.add I have:
    Code:
    dhcp-host=3C:8D:20:...,192.168.2.154,GHubKitchen
    If I ssh into the router, and do "nslookup 192.168.2.154" it resolves to the above name. If I run "arp" it responds with that name. If I look in dnsmasq.leases it is in there with that name. But the network map in the UI shows it as "Google-Nest-Hub".

    Is there anything I can do besides manually overriding the names for each device in the UI? Did I miss anything. Any tips would be appreciated. Thanks!
     
  2. Sky

    Sky Regular Contributor

    Joined:
    Jul 19, 2018
    Messages:
    81
    Location:
    PDR of California
    Why not just let the router handle DHCP automatically? Are the clients poor at reconnecting if the IP changes after a reboot? Routers do a very good job of DHCP, which is part of their integral design.
     
  3. logicalmind

    logicalmind New Around Here

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    May 26, 2020
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    The underlying problem is that many of the devices do not accept host names. So I end up with like 5 "Google-Nest-Hub" and no clue which is which. But the primary reason is for traffic analysis. I have a number of tv's and they're samsung. All of them show up as localhost. And I'm trying to monitor their traffic or at least know which ones are being nosey or heavily spying. The traffic analysis just shows up with 5 localhosts and I'd have to further identify them by mac id. I already went through my house and identified every device and mac id and I have to manually create the mapping in multiple places for all this work. I'd prefer to just do it in dhcp, which then works for dns, but it doesn't work within any of the tools in the router UI.

    Additionally, I have 3 asus routers. Only one does the dhcp and the other two are just AP's, but I have to maintain this manual list of mac/ip/hostname across all 3 for any of the UI tools to work. I have over 70 devices on my wifi (light switches, fans, tv's, etc.) and it would be much easier to maintain them all in one place.
     
  4. Sky

    Sky Regular Contributor

    Joined:
    Jul 19, 2018
    Messages:
    81
    Location:
    PDR of California
    OK, now it makes more sense. Check the FW limitation for how many devices you are allowed to reserve IPs. (OEM on the AC87 is 64, ymmv on your device or with Merlin.)

    I had the same issue with my Samsung TVs. This issue is with the TVs not with the router. Samsung has known about this for several years but refuses to address it. The Samsungs like to act like their own little network sometimes (Wi-Fi Direct), especially if you use something like a wireless keyboard to access the TV. Methodically check your settings on the TVs. You may have to do a manual factory reset to get them to stop trying to act as local hosts. It's a genuine PIA and will take an inordinate amount of time. For sometime ASUS had an issue with their logging that kept registering the LocalHost issue from those TVs repeatedly. That has been addressed in the OEM FW, can't say about Merlin though.

    As for the Google Nests, you may just have to do the unplug-wait-plugin ... one-at-a-time method to ID each of them, then label each as you reserve their IPs.

    You may want to try a different method of reserving the IPs you need. In the OEM the alternate to LAN > DHCP Server > Manually Assigned IP around the DHCP List (Max Limit: 64) is Network Map > (cicular Client button) > Client Status > (device) > MAC and IP Address Binding on-off. The Client Status > (device) > MAC and IP Address Binding slider does not populate the DHCP List but does reserve the IP address. I don't know the magic and don't know if it holds true for Merlin, or even if Merlin has that but I'm assuming it does.

    Perhaps one of the members using Merlin will chime in with better info.
     
  5. dev_null

    dev_null Regular Contributor

    Joined:
    Nov 9, 2019
    Messages:
    85
    Location:
    Metro-west, MA
    Take a look at this thread: https://www.snbforums.com/threads/identifying-wireless-client.64434/.

    Using the dnsmasq approach takes an IP renewal or two before the names are correctly displayed. Shorten the lease period overall or per device and it should show up.

    EDIT: it may also have to do with the device name length. I use 8-10 characters... maybe try to shorten the name? Or do one without spaces (I use dashes and underscores rather than spaces).
     
    Last edited: Jun 3, 2020