We found a bug.
In some places of our network after changing SPS2024 to SG300 switches we hear about problem every one-two weeks.
When problem arrives, switch seems to be working as usual, nothing strange in log, but users havent connectivity with bras untill somebody reboots switch.
Now i select one building to define symptom. There SG300-52 is used with fw 1.3.0.62. Our commonly used configuration:
ports 1-48 - untagged users (ip source-guard, storm-control, port security, service-acl with 7 rules), 1 vlan per building
port 49-51 - downlinks to other switch (trunk, dhcp snoop trust and DAI trust)
port 52 uplink, configured same as downlinks.
DHCP Snoop, DAI, IP source guard configured globally and on users vlan.
After problem arrives i attach notebook to user port and see no arp packet from core in wireshark dump, only packets from other users.
From core side i see arp request only from hosts from ports on right half of switch (13-24,37-52)
If i move uplink cable from port 52 to port 50 - connectivity arrives!!!
I think this is a big problem with DAI code.
Now i set real ip to switch, disables DAI on users VLAN and return uplink to 52 port.
I can give ip and password to cisco stuff to debug it before reboot.