Switch 1810G FTP Problem over Fiber Connection

[Rusch]

we have two Gigabit Switches of the same kind:
HP ProCurve 1810G - 24 GE, P.1.17, eCos-2.0
each have port 24 equipped with a Fiber Module
1000MbpsFullDuplexFiberSX is the connection over an 80m distance between both
This is our LAN setup:

servers and workstations(VT1) -- switch1 ---- fiber ----switch2 -- workstations(VT2)

All workstations at location VT2 suffer from the same FTP problem:
We can establish a connection to the servers with ftp clients, we can login sucessfulle, but when doing a simple "ls" the ftp traffic stalls completely, no more packets, it hangs completely, the session is dead after that.
When doing the same thing from location VT1, everything is fine. We even took one of the PCs from VT2 and plugged it in at VT1, then it worked as expected.
So there must be some very low level network problem either at the switch at VT2 or with the traffic going over that fiber link between the two switches.
BTW: ther are no errors at all when looking at the logs of the switches.
So what is so special about FTP ?

Any hints much appreciated.

I will collect the serial numbers for those devices tommorrow (not onsite today) and start a support case with HP.

P.S. This thread has been moved from Switches, Hubs, Modems (Legacy ITRC forum) to Web and Unmanaged. -HP Forum Moderator

[Jack Howes]

FTP uses two different TCP ports. Port 21 is for communications, i.e. login, set transfer type etc. When you do an "ls" ftp uses another TCP port to transfer the data. It looks like something is blocking the communications on the other port. The other port is usually a random port established when the ftp session is started. Since you moved a workstation that wasn't working from VT2 to VT1 and it worked that means its not a PC firewall issue. Can you run wireshark on the failing PC and then on the FTP server to see if the communications are getting to the FTP server?

/jack

[Rusch]

We got Firmware Update P1.18 from HP Support this morning and have no problems anymore since the updates on both switches. This had nothing to do with the clients or the servers.

[Jack Howes]

Good to know about the FW update fixing the problem. I'll look for the release notes to see what was fixed.