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Chris_Grabill_2's avatar
Chris_Grabill_2
Icon for Nimbostratus rankNimbostratus
Jun 09, 2015

Passive FTP session load balancing from the same client

I have a situation that I cannot figure out and I need some help. I have a virtual server set up for passive FTP load balancing to a pool of four members.

 

Right now it is set up as Performance (Layer 4), TCP and a service port of 0.

 

I have source-address-translation set to automap and a protocol profile of fastL4 with a 3600 second timeout.

 

I have source_addr persistence with Mirror Persistence, Match across Services, and Match Across Virtual Servers all checked.

 

There is also an iRule on there that looks like this to only accept the 50000-50020 and port 21 range.

 

Right now there is really only one client FTPing in and doing gets over four sessions. The problem I have is I would like to see each of his sessions load balanced to a different server in the pool. Can I do this? And how would I do it?

 

when CLIENT_ACCEPTED {

 

if {([TCP::local_port] >= 50000 && [TCP::local_port] <= 50020) || [TCP::local_port] == 21} { } else { drop } }

 

application delivery
design
devops
iRules
LTM
passive ftp
performance

8 Replies

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  • kridsana's avatar
    kridsana
    Icon for Cirrocumulus rankCirrocumulus
    Jun 10, 2015

    From my understanding.

     

    If you use persistence, you can't load balance across pool member (F5 will send to only one member)

     

    Can you just remove persistence profile from virtual server ? Is FTP working properly if remove it?

     

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Jun 10, 2015

    without ftp profile, bigip does not relate control and data channels together. now, both control and data channels are sent to the same server because of source address persistence. since there is only one client but multiple sessions, you cannot load balance ftp sessions.

     

    to make it, i understand you need ftp profile and source address persistence should not be needed.

     

    • Chris_Grabill_2's avatar
      Chris_Grabill_2
      Icon for Nimbostratus rankNimbostratus
      Jun 11, 2015
      So if I change this to 21 source port and an FTP profile I don't need source_addr persistence? Then each session will load balance to the next server? I would think you need the source address persistence to keep the data and control channels together.
    • nitass's avatar
      nitass
      Icon for Employee rankEmployee
      Jun 12, 2015
      yes. i do not think you need persistence because ftp profile should bind control and data channels together.
  • nitass_89166's avatar
    nitass_89166
    Icon for Noctilucent rankNoctilucent
    Jun 10, 2015

    without ftp profile, bigip does not relate control and data channels together. now, both control and data channels are sent to the same server because of source address persistence. since there is only one client but multiple sessions, you cannot load balance ftp sessions.

     

    to make it, i understand you need ftp profile and source address persistence should not be needed.

     

    • Chris_Grabill_2's avatar
      Chris_Grabill_2
      Icon for Nimbostratus rankNimbostratus
      Jun 11, 2015
      So if I change this to 21 source port and an FTP profile I don't need source_addr persistence? Then each session will load balance to the next server? I would think you need the source address persistence to keep the data and control channels together.
    • nitass_89166's avatar
      nitass_89166
      Icon for Noctilucent rankNoctilucent
      Jun 12, 2015
      yes. i do not think you need persistence because ftp profile should bind control and data channels together.
  • giltjr's avatar
    giltjr
    Icon for Nimbostratus rankNimbostratus
    Jun 10, 2015

    I don't think you are going to be able to load balance the data connections. Unless you have some magic FTP server the data connection must go back to the same server that the control connection is on.

     

    When doing passive FTP the server opens a port to do the data transfer on and then tells the client what port it opened. The client the connects to that port. So if the control connection is to server 1 it will open the port for the data transfer, if you try to send the inbound request from the client to server 2, server 2 will not know anything about that port.