Strange packet loss on a V1910-24G SWITCH

[SSinternalIT]

Hello everyone!

I'm experiencing a strange behaviour with the HP switch in the subject (also identified in the web interface as: 3Com Baseline Switch 2928-SFP Plus Software Version Release 1101P10).

I have some LinkSys SRW2048 connected together and the new HP is also connected to one of those (we aggregated two ports and used those as an uplink).

I connected various devices (firewalls, routers mostly) and they are reachable from the PCs and servers  connected on the linksys switches.

I added two juniper SSG20 on the HP switch and they are not reachable anymore from the Linksys switches. When the same juniper SSG20 are connected on the LinkSys they are reachable also from the HP.

If I connect to the linksys a cheap TP-LINK managed switch I have no problem with the juniper SSG-20 connect to it and I can also reach the juniper from the HP (through the LinkSys).

I also observed the same issue with a Thecus NAS with two network card in teaming for load balancing, and a couple of servers.

Is there anyone that can shed some light on this?

Thank you very much in advance for any help!