TCP data transfering feature

[Shelley Zhou]

Network environment:

Two HP servers (hostname MD1 and MD2, HW rp5470, IP address 192.168.20.46 for MD1 and 192.168.20.45 for MD2) connected into same VLAN together with Firewall (IP address 192.168.20.41). The servers MD1 and MD2 is working as FTP server.
Behind Firewall my customer is FTPing files from MD1 and MD2 from the same host using same IP address.

Problem:
It's very quick to transfer files from MD2 for my customer while it's very slow to transfer files from MD1.

Workaround:
I tested to FTP from Firewall to MD1 using same username for my customer, it's very quick.

I logged the packets on the interface card when my customer was FTPing files from MD1. It showed that MD1 waited for ACK from client after each sent TCP segment even though the window size on sever side is 57344 and 24820 on client side.
I did same kind of log on MD2. The log showed that MD2 sent several segments before it waited for ACK.

Question:
How to configure TCP parameters on server MD1 to make it transfer several TCP segments before waiting for ACK?
Is TCP parameters same for all users? I.e would different users get different TCP performance if all other conditions are same?

I also attach one log file which you can open via Ethereal or Wireshark.

Thank you very much for your help and look forward to your advice!

Best Regards
Shelley Zhou

[Steven E. Protter]

Shalom Shelly,

Don't see an attachment.

However a lack of data never stopped me before.

Suggestion:

lanadmin the interfaces

if you are using lan0 then:

lanadmin 0

You may find the network interface on the slow server is running at half duplex.

SEP

[Shelley Zhou]

Hi Steven,

Thanks very much for your advice!
I have just checked the network interface card, it is indeed Full Duplex, 100M Fast Ethernet both on server side and switch side.

Tried to attach log file, obviously it didn't work. Could you give me your e-mail address so I can send it to you if you don't mind?

Br, Shelley

[Ludovic Derlyn]

hi

just a question, which is order to send files ?

Problem occurs when send files to 1 server is very slow and second server is faster ?
perhaps a problem with firewall cache or other ...

Regards

L-DERLYN

[Dennis Handly]

>Tried to attach log file, obviously it didn't work.

Did you try to attach a text file?

[Shelley Zhou]

Hi,

Concerning attachment, it worked whey I replied. But the first time when I sent my question, it didn't work, it's a binary file with captured packets on the network interface.
*****************************************
My customer keep on fetching files from both servers all the time, but it's slow to fetch files from first server, while very fast from the second server.

From customer to the servers, it's same route, ie it goes through the same firewall.

[Ludovic Derlyn]

hi,

attachment is working , open it with ethereal is ok

Have you tested to send file first by second server, and after by first server (file may be in "cache of firewall (sorry for my english))

Regards

L-DERLYN