rule to replace vip ip with pool member

I think a stream will only act on the HTTP payload, not the headers. You'll probably want to use an iRule for this...here's something that will hopefully get you close (not tested):

  
 when HTTP_REQUEST {  
 HTTP::header replace Host [LB::server addr]:[LB::server port]  
 }  
 

-Matt

That will not work for this. It's an oracle connection SID in the tcp payload.

 

 

Connect Data: (DESCRIPTION=(CONNECT_DATA=(SID=lenvdbq)(CID=(PROGRAM=)(HOST=__jdbc__)(USER=)))(ADDRESS=(PROTOCOL=tcp)(HOST=10.10.10.11)(PORT=11500)))

 

 

My vip address is 10.10.10.11 and I need to replace it with the selected pool members address.

 

 

-sp1at

In that case, I think you'll work (from a connectivity standpoint) without any issues. Ideally setup the oracle client to point to the virtual server address in tnsnames.ora as opposed to the real server address. The BigIP is a NAT device, so as the traffic flows through the BigIP it'll do destination address translation back to the selected server.

 

 

Now for the big caveat: if you're looking to load balance read/write operations be super careful - this is an extremely tricky problem to solve. If you're doing read only, you'll likely be OK.

 

 

-Matt

If you want to rewrite the TCP payload, I think you'd need to enable the stream filter in CLIENT_ACCEPTED. Enabling the stream filter in SERVER_CONNECTED only seems to allow you to rewrite the response from the server to LTM.

Normally, a load balancing decision isn't made until LB_SELECTED. However, you can force a load balancing decision in CLIENT_ACCEPTED using LB::select (Click here. You could then get the selected server IP using [LB::server addr].

  
 when CLIENT_ACCEPTED {  
  
     Make a load balancing decision 
    set lb_select [LB::select]  
  
     Now use the selection 
    eval $lb_select  
  
     Replace the virtual server IP with the selected pool member IP 
 STREAM::expression "@[IP::local_addr]@[LB::server addr]@"  
  
     Enable the stream filter 
    STREAM::enable  
  
    log local0. "Stream expression: @[IP::local_addr]@[LB::server addr]@"  
 }  
 

Aaron