FTPS with ACE 4710

Question

Hi,
I need to configure ACE for load-balancing FTPS. And simply deploying L4 policies are not helping either. Configured the FTPS servers and both of them are working fine when accessed via physical IP, but do not work when accessed via the VIP.
if it is possible, a reference URL would really be a great help.

Answer 1

Hi Rajiv,
Do you want to loadbalance SFTP ?
Or just have it pass through ??
Loadbalancing SFTP is difficult because it starts as regular FTP and switches over to SSL which ACE can't do and fails to understand.
you don't need anything to have it passthrough.
As long as you don't ask ACE to inspect the traffic, and assuming this traffic is permitted in your access-group, then there is nothing to do to have it go through.
I think your goal is to distribute inbound file deposits evenly across SFTP servers.
High-level Overview
Clients -> Internet -> Tier-1 Firewall -> ACE Load-balancer -> SFTP Servers
I would like to tell you that SFTP is nothing but SSH. It uses a single connection. There are no issues loadbalancing it using traditional Layer 4 load balancing.
So you are good.
On the other hand FTP over SSL (FTPS) can neither offloaded nor loadbalanced using ACE.
FTPS uses multiple channels and Since the control channel is encrypted, ACe is not able to get the port numbers for the data connections.
Kindly find these examples for FTP load balance method in cisco ACE:
1. FTP serverfarm on Cisco ACE
http://snippets101.blogspot.com/2007/06/ftp-serverfarm-on-cisco-ace.html
2. FTP Load Balancing on ACE in Routed Mode Configuration Example
http://docwiki.cisco.com/wiki/FTP_Load_Balancing_on_ACE_in_Routed_Mode_Configuration_Example
3. FTP Load Balancing on ACE in One-Arm Mode Configuration Example
http://docwiki.cisco.com/wiki/FTP_Load_Balancing_on_ACE_in_One-Arm_Mode_Configuration_Example
Kindly refer the folowing URL for Layer4 policies:
http://cisco.com/en/US/products/hw/modules/ps2706/products_configuration_example09186a00809c3048.shtml
http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/classlb.html
http://docwiki.cisco.com/wiki/Cisco_Application_Control_Engine_(ACE)_Module_Troubleshooting_Guide,_Release_A2(x)_--_Troubleshooting_Layer_4_Load_Balancing
http://snippets101.blogspot.com/2008/08/cisco-ace-and-private-vlans-in-switch.html
http://snippets101.blogspot.com/2008/08/asymmetric-server-normalization-on.html
http://docwiki.cisco.com/wiki/Cisco_ACE_4700_Series_Appliance_Quick_Start_Guide,_Release_A3(1.0)_--_Configuring_Server_Load_Balancing
http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA1_7_/configuration/security/guide/tcpipnrm.html#wpmkr1116809
Hope it will help you furhter in configuring the ACE load balancing L4 policies.
Kindly rate
Sachin Garg