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I am experiencing frequent disconnects on my home ADSL connection (it drops several times a day). My setup is a Netgear R7000 running DD-WRT, connected to a D-Link DSL-320B running in bridging mode.

Whenever the connection drops, the DD-WRT syslog shows entries like this:

Jun 4 11:02:13 DD-WRT kern.info kernel: device vlan2 entered promiscuous mode
Jun 4 11:02:14 DD-WRT kern.info kernel: device vlan2 left promiscuous mode
Jun 4 11:02:14 DD-WRT user.info syslog: pppd : PPP daemon successfully stopped
Jun 4 11:02:14 DD-WRT daemon.info pppd[531]: Exit.

Is 'promiscuous mode' the cause of the connection drop, or merely a result of it? If it isn't the cause, is there anything else I can do on the router to try and help identify the problem?

Edit: Screenshot of my vlan setup (from Setup -> VLANs):

enter image description here

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  • Why is the router set to use promiscuous mode? This will probably not work on WPA or WPA2, so which security protocol are you using?
    – harrymc
    Jun 7, 2015 at 19:10
  • My wifi is using WPA2. I've not enabled promiscuous mode (as far as I know) - I'm still not completely clear what promiscuous mode is. The log entries seem to indicate that the router enters this mode when the connection drops rather than being in it all the time. Jun 7, 2015 at 20:18
  • What is your vlan2 of your DD-WRT connected to? On my DD-WRT, vlan 0 is LAN (4-port switch) and vlan 1 is WAN. Also, make sure your DHCP lease for WAN IP is not a small duration like 10 minutes. It is known to cause connection loss.
    – some user
    Jun 8, 2015 at 4:48
  • @someuser I've added a screenshot of my vlan setup to the question. I think this indicates that vlan2 is WAN. How do I check the DHCP lease for the WAN IP? Jun 9, 2015 at 13:43
  • Your screenshot shows you have your LAN and WAN ports bridged to the same switch, as if you had plugged your WAN cable into a LAN port. This is an odd setup to say the least...
    – qasdfdsaq
    Jun 9, 2015 at 14:42

1 Answer 1

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Looks to me like promiscuous mode is a result of the connection drop in this case. In any case, a more complete log would be helpful.

Promiscuous mode means an interface receives and processes all inbound traffic, not just traffic directed at itself. It is not a normal mode of operation, and is usually used for traffic sniffing, or occurs when an interface has been reset or is an initializing state, e.g. if a cable is replugged or a device at the other end is rebooted.

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  • Are you aware of any way to get a better log? The excerpt from the DD-WRT router syslog I included in the question is literally all that appears when the disconnects occur. Jun 9, 2015 at 14:56
  • I meant more of the log (i.e. previous lines). That said you can SSH in and run the ppp daemon by hand with debugging switch enabled which might give you more info: tldp.org/HOWTO/PPP-HOWTO/x1290.html
    – qasdfdsaq
    Jun 9, 2015 at 15:00
  • There's nothing else of the log to include, the line before vlan2 entering promiscuous mode will be from several hours earlier. You have given me some things to look at though, so thanks. Jun 11, 2015 at 11:58

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