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SG300 - vlan setup automagically changing...


Seem to have weird problem.....I have 2 SG300 switches, in layer3 mode, lag'd together for high availability, serving 2 Dell R815's and a Dell Equallogic 4100 for virtualisation. I have setup a number of vlan's, network traffic, mgmnt traffic, iScsi, vMotion etc and they seem to work.

However, Equallogic unit suddenly became unavailable to view for managment yet maintained iscsi traffic for the servers ok. After much head scratching, noticed that one of my SG300's had the vlan ports assigned to various vlans had *automagically* changed there assignment, ie tagged changed to excluded, but only for one of the iscsi traffic connections and the mgmnt port, both coming from the Equallogic, the other iscsi continued its assignment fine. The other SG300 hasn't changed. Guaranteee no one has been into change it and no changes have been made to Dell servers or Equallogic.

Q. Is there any circumstance where the switch can change the port setup itself? or is there any external circumstance that would trigger that change either?                  

This has now occured twice. The setup is running as a test lab, not in production until all setup is complete, then it will replace our existing harware.


Thx in advance,


Everyone's tags (2)

SG300 - vlan setup automagically changing...

Hi Bryan,

Yes, I've experienced this "automagic" as well... its exciting. Cisco calls it "smartport." In the web ui, go to smartport -> properties, and uncheck all those boxes, choose diable, etc. Also be sure to disable as much as you can under smartport -> interface settings.  I've also had issues with the voice vlan magically change itself as well with the sg300, so I disabled that as well on mine and statically configured everything.

Just as a side note, with the SG300 switches, they are small business switches, so this post probably would have gotten seen quicker in the small business - switches forum.



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