Sunday, 27 May 2018 | tralala:)

DLink DGS-3100-48 asymmetric VLAN (private VLAN) issues

For a recent project a have to deploy private VLAN (asymmetric VLAN in DLink’s terminology) using DGS-3100-48 switch.

Using the latest available firmware version 3.60.28 I wasn’t able to configure it properly. In other words – the switch doesn’t support asymmetric VLAN properly. Note: since firmware version v3.00.43 there should be support for asymmetric VLAN so one would expect it could work (

It’s time for DLink support!

After few emails with support department of DLink I have receive a new firmware 3.60.37. Since I have six DGS-3100-48 units in stack I have uploaded new firmware to all of them - as a stack. And this is where it gets interesting. 4 of 6 switches failed to load and ends up in booting loop.

After decompressing image you can see something like that on the console output:

01-Jan-2000 01:01:16 %ERHG-F-SEND: Bad parameters in HSG_init_hash

***** FATAL ERROR *****

Reporting Task: ROOT.

Software Version: 3.60.37 (date  14-Nov-2010 time  14:52:42)










*****************  SYSTEM RESET  *****************


There is not much to do as you cannot reset the configuration during the boot, so the only option was…

Time for recovery procedure!

Manual v3.6 says something about password recovery procedure – which you can utilize to reset configuration (it’s always worth a try to do so before changing fw boot or reflashing). According to manual you should:

„Power on the switch. After the boot image is loaded to 100%, the Switch will allow 2 seconds for the user to press the hotkey (Shift + 6 ) to enter the “Password Recovery Mode”.“

But this doesn’t work – absolutely not. It may for older fw but it definitely does not for this one.

There is this HW installation guide v3.5 that also lacks any details for recovery procedure. However v1 of the same guide has the following information: During the boot process, after the first part of the POST is completed press <Esc> or <Enter> within two seconds after the following message is displayed:

Autoboot in 2 seconds -press RETURN or abort and enter prom.

Well, this is still unusable since no 2 seconds pause is visible during the switch boot.

Time for solution!

Finally DLink support personal come up with solution: right after the POST press the CTRL+SHIFT+ ”-“ one time! This shows the “Autoboot…” message and you can press ESC to enter the service menu. From service menu navigate to advanced menu (via shift + 6) and remove config/change the boot image etc.

Btw; Asymmetric VLAN doesn’t work with firmware 3.60.37 anyway. In the end we have received version v3.60.44 which does work correctly, finally.

1 comment

  1. This atricle is a home run, pure and simple!

    — Lonitra Sat, 20 Apr 2013

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