Configuring CSM to Load Balance SSL to a Farm of SCAs for One-Armed Proxy Mode

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Updated:September 11, 2018
Document ID:26341

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Introduction

This document provides a sample configuration for the Content Switching Module (CSM) load balance of Secure Socket Layer (SSL) traffic to a farm of Secure Content Accelerators (SCAs). The configuration is for SCAs in nontransparent proxy mode with connection in one-port mode.

In nontransparent mode, the SCA uses the SCA IP address as the source for plain-text connections to the web servers.

Note: Use two different VLANs/IP subnetworks for the SCAs and the web servers; one subnetwork is for all SCAs, and a separate subnetwork is for all web servers. If you place both farms in the same Layer 2 (L2) domain, source Network Address Translation (NAT) is necessary. Source NAT guarantees that packets return to the CSM and that the Catalyst hardware does not simply L2 switch the packets.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these VLANs/subnetworks:

  • Client side: Virtual IPs (VIPs) and upstream router (Multilayer Switch Feature Card [MSFC])

  • Catalyst 6500/6000 with CSM in Slot 5

  • Server side 1: web servers

  • Server side 2: SCAs

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) .

Network Diagram

This document uses this network setup:

oap_26341-a.gif

Configurations

This document uses these configurations:

  • Catalyst 6000/CSM Slot 5

  • SCA 1

  • SCA 2

Catalyst 6000/CSM Slot 5 

!--- This is the configuration of nontransparent SSL load balance.

Cat6k# show running-config | begin Module 5
module ContentSwitchingModule 5
 vlan 6 client
  ip address 10.10.10.200 255.255.255.0
  gateway 10.10.10.1

!--- This is the CSM IP address on the client side and !--- CSM upstream gateway (the MSFC).

!
 vlan 4 server
  ip address 192.168.1.1 255.255.255.0

!--- This is the CSM IP address on the SCA server farm VLAN. !--- SCAs use this IP address as the default gateway.

!
 vlan 10 server
  ip address 192.168.2.1 255.255.255.0

!--- This is the CSM IP address on the web server farm VLAN. !--- The web servers use this IP address as the default gateway.

!
 static drop
  real 192.168.2.0 255.255.255.0

!--- This drops every new connection that the web servers originate, !--- unless the connection matches a VIP.

!
 serverfarm SCA443
  nat server

!--- When connections are directed to this server farm, !--- the IP address of the SCA selection replaces !--- the destination IP address.

  no nat client
  real 192.168.1.250 443
   inservice
  real 192.168.1.251 443
   inservice

!--- The configurations of both SCAs are such that, !--- with the send of a connection to this server farm, the destination port !--- translates to 443. In this example, there is no translation, as !--- the VIP listens to port 443. !--- This is different in the following server farm, SCA444.

!
 serverfarm SCA444
  nat server
  no nat client
  real 192.168.1.250 444
   inservice
  real 192.168.1.251 444
   inservice

!--- With the selection of this server farm, there is a !--- modification of connections that go to either SCA. !--- The destination IP changes to match the IP of one of the SCAs !--- (NAT server), and the destination port becomes 444.

!
 serverfarm WEBFARM
  nat server
  no nat client
  real 192.168.2.10 80
   inservice
  real 192.168.2.11 80

!--- Specify port 80 to translate from port 81 inservice. !--- (The SCA communicates on port 81, according to the SCA setup.) !--- This is a standard web server farm.

!
 sticky 10 ssl timeout 60
 sticky 20 ssl timeout 60

!--- This creates two distinct sticky groups with SSL ID as a basis. !--- The timeout is 60 seconds.

!
 vserver TESTSITE1
  virtual 10.10.10.10 tcp https
  serverfarm SCA443
  sticky 60 group 10
  persistent rebalance
  inservice

!--- The vserver for the first site (www.testsite1.com) listens !--- to 10.10.10.10 on port 443. !--- Connections go to the SCAs without a change in the !--- destination port. (See the configuration of server farm SCA443.)

!
 vserver TESTSITE2
  virtual 10.10.10.20 tcp https
  serverfarm SCA444
  sticky 60 group 20
  persistent rebalance
  inservice

!--- The vserver for the second site (www.testsite2.com) listens !--- to 10.10.10.10 on port 443. !--- Connections go to the SCAs and change the !--- destination port to 444. (See the configuration of server farm SCA444.)

!
 vserver WEB-DECRYPT
  virtual 10.10.10.100 tcp 81
  serverfarm WEBFARM
  persistent rebalance
  inservice
!

!--- This is the vserver for the plain-text connections. !--- This vserver receives connections on port 81 from the SCAs. !--- As the configuration of this vserver does not specify a VLAN, !--- the vserver can also receive connections directly !--- from the client side. !--- To prevent direct client access of this VIP, !--- you can use the VLAN 4 option. !--- You can also place this VIP in the SCA subnetwork. In that case, !--- clients do not even have a route to that subnetwork. (Clients only !--- have a route if you configure the upstream router !--- with a static route.)

SCA 1 

!--- This configures SCA in one-port, nontransparent mode. 

sca1# show run 
# 
# Cisco CSCA Device Configuration File 
# 
# Written:      Sun Feb  6 01:46:35 2106 
# Inxcfg:       version 2.3 build 200108071342 
# Device Type:  CSS-SCA 
# Device Id:    S/N 119cd6 
# Device OS:    MaxOS version 2.5.1 build 200108071341 by Dan L. Reading 

### Device ### 

mode one-port 
ip address 192.168.1.250 netmask 255.255.255.0 
hostname sca1 
password enable 
"2431245A572441713173717748626D734B35516B794F64336A51652F" 
no ip domain-name 
no rdate-server 
timezone "MST7MDT" 
no rip 
ip route 0.0.0.0 0.0.0.0 192.168.1.1 metric 1 

### Interfaces ### 

interface network 
  auto 
end 
interface server 
  auto 
end 

### Remote Management ### 

no remote-management access-list 
remote-management enable 

### SNMP Subsystem ### 

no snmp 
telnet enable 
no telnet access-list 
web-mgmt enable 
no web-mgmt access-list 

### SSL Subsystem ### 

ssl 
  server test1 create 
    ip address 10.10.10.100 
    sslport 443 
    remoteport 81 
    key default 
    cert default 
    secpolicy default 
    cachesize 20 
    no transparent 
  end 
  server test2 create 
    ip address 10.10.10.100 
    sslport 444 
    remoteport 81 
    key default 
    cert default 
    secpolicy default 
    cachesize 20 
    no transparent 
  end 
end 
sca1#

SCA 2 

!--- This configures SCA in one-port, nontransparent mode.

sca2# 
sca2# show run 
# 
# Cisco CSCA Device Configuration File 
# 
# Written:      Fri Feb 13 21:18:29 1970 
# Inxcfg:       version 2.3 build 200108071342 
# Device Type:  CSS-SCA 
# Device Id:    S/N 119ca2 
# Device OS:    MaxOS version 2.5.1 build 200108071341 by Dan L. Reading 

### Device ### 

mode one-port 
ip address 192.168.1.251 netmask 255.255.255.0 
hostname sca2 
password enable 
"2431245A572441713173717748626D734B35516B794F64336A51652F" 
no ip domain-name 
no rdate-server 
timezone "MST7MDT" 
no rip 
ip route 0.0.0.0 0.0.0.0 192.168.1.1 metric 1 

### Interfaces ### 

interface network 
  auto 
end 
interface server 
  auto 
end 

### Remote Management ### 

no remote-management access-list 
remote-management enable 

### SNMP Subsystem ### 

no snmp 
telnet enable 
no telnet access-list 
web-mgmt enable 
no web-mgmt access-list 

### SSL Subsystem ### 

ssl 
  server test1 create 
    ip address 10.10.10.100 
    sslport 443 
    remoteport 81 
    key default 
    cert default 
    secpolicy default 
    cachesize 20 
    no transparent 
  end 
  server test2 create 
    ip address 10.10.10.100 
    sslport 444 
    remoteport 81 
    key default 
    cert default 
    secpolicy default 
    cachesize 20 
    no transparent 
  end 
end 
sca2#

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output. 


!--- A client opens a connection to www.testsite1.com.

Cat6k# show module csm 5 vserver detail
TESTSITE1, state = OPERATIONAL, v_index = 10
  virtual = 10.10.10.10/32:443, TCP, service = NONE, advertise = FALSE
  idle = 3600, replicate csrp = none, vlan = ALL, pending = 0
  max parse len = 600, persist rebalance = TRUE
  conns = 1, total conns = 1
  Default policy:
    server farm = SCA443
    sticky: timer = 60, subnet = 0.0.0.0, group id = 10
  Policy           Tot Conn     Client pkts  Server pkts
  ------------------------------------------------------
  (default)        1            9            11

!--- The client connection to port 443 hits the vserver TESTSITE1 !--- and is load balanced to an SCA.

TESTSITE2, state = OPERATIONAL, v_index = 11
  virtual = 10.10.10.20/32:443, TCP, service = NONE, advertise = FALSE
  idle = 3600, replicate csrp = none, vlan = ALL, pending = 0
  max parse len = 600, persist rebalance = TRUE
  conns = 0, total conns = 0
  Default policy:
    server farm = SCA444
    sticky: timer = 60, subnet = 0.0.0.0, group id = 20
  Policy           Tot Conn     Client pkts  Server pkts
  ------------------------------------------------------
  (default)        0            0            0

WEB-DECRYPT, state = OPERATIONAL, v_index = 13
  virtual = 10.10.10.100/32:81, TCP, service = NONE, advertise = FALSE
  idle = 3600, replicate csrp = none, vlan = 4, pending = 0
  max parse len = 600, persist rebalance = TRUE
  conns = 1, total conns = 1
  Default policy:
    server farm = WEBFARM
    sticky: timer = 0, subnet = 0.0.0.0, group id = 0
  Policy           Tot Conn     Client pkts  Server pkts
  ------------------------------------------------------
  (default)        1            7            5

!--- The SCA opens a connection to 10.10.10.100 port 81, !--- which is load balanced to a web server.

Cat6k# show module csm 5 conns detail

    prot vlan source                destination           state
----------------------------------------------------------------------
In  TCP  4    192.168.1.250:4376    10.10.10.100:81       ESTAB
Out TCP  10   192.168.2.11:81       192.168.1.250:4376    ESTAB
    vs = WEB-DECRYPT, ftp = No, csrp = False

!--- This provides details of the connection from the SCA to the web server. !--- The connection comes from VLAN 4 (the SCA VLAN), destined to !--- 10.10.10.100 port 81. !--- This is different from what happens in transparent mode. !--- In this case, the SCA opens the connections with use of !--- the SCA IP address, 192.168.1.250. The server does not see the IP !--- of the original client. !--- The connection goes to VLAN 10 (web servers VLAN) !--- to the web server selection. (The destination IP address !--- changes accordingly. The port does not change.) !--- If the servers listen to port 80 instead of port 81, you can configure !--- the translation of the destination port. You can add a port !--- to the definition of the real servers.


!--- NOTE: The Out line swaps source with destination. !--- "Out" refers to the return traffic packets that the CSM !--- receives from that VLAN.

In  TCP  6    10.15.0.50:2324       10.10.10.10:443       ESTAB
Out TCP  4    192.168.1.250:443     10.15.0.50:2324       ESTAB
    vs = TESTSITE1, ftp = No, csrp = False

!--- This provides details of the connection from the client to the VIP. !--- The connection comes from VLAN 6 (the client VLAN), destined to !--- 10.10.10.10 port 443. !--- The connection goes to VLAN 4 (the SCA VLAN) !--- to the SCA selection. The destination IP changes !--- from the 10.10.10.10 (the VIP) to 192.168.1.250 (the SCA), !--- as the server farm had the option NAT server. !--- This is different in nontransparent mode. !--- The same client opens a second connection, !--- this time to www.testsite2.com.

Cat6k#
Cat6k# show module csm 5 conns detail

    prot vlan source                destination           state
----------------------------------------------------------------------
In  TCP  4    192.168.1.250:4377    10.10.10.100:81       ESTAB
Out TCP  10   192.168.2.10:81       192.168.1.250:4377    ESTAB
    vs = WEB-DECRYPT, ftp = No, csrp = False

!--- This connection is from SCA to VIP .100, load balanced to !--- web server .10.

In  TCP  4    192.168.1.250:4376    10.10.10.100:81       ESTAB
Out TCP  10   192.168.2.11:81       192.168.1.250:4376    ESTAB
    vs = WEB-DECRYPT, ftp = No, csrp = False

!--- This connection is from SCA to VIP .100, load balanced to !--- webserver .11.

In  TCP  6    10.15.0.50:2325       10.10.10.20:443       ESTAB
Out TCP  4    192.168.1.250:444     10.15.0.50:2325       ESTAB
    vs = TESTSITE2, ftp = No, csrp = False

!--- This connection is from client to VIP .20, load balanced to !--- SCA .250, port 444.

In  TCP  6    10.15.0.50:2324       10.10.10.10:443       ESTAB
Out TCP  4    192.168.1.250:443     10.15.0.50:2324       ESTAB
    vs = TESTSITE1, ftp = No, csrp = False

!--- This connection is from client to VIP .10, load balanced to !--- SCA .250, port 443.

Cat6k#show module csm 5 real detail
192.168.2.10, WEBFARM, state = OPERATIONAL
  conns = 1, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 1
  total conns established = 1, total conn failures = 0
192.168.2.11, WEBFARM, state = OPERATIONAL
  conns = 1, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 1
  total conns established = 1, total conn failures = 0
192.168.1.250:443, SCA443, state = OPERATIONAL
  conns = 1, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 1
  total conns established = 1, total conn failures = 0
192.168.1.251:443, SCA443, state = OPERATIONAL
  conns = 0, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 0
  total conns established = 0, total conn failures = 0
192.168.1.250:444, SCA444, state = OPERATIONAL
  conns = 1, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 1
  total conns established = 1, total conn failures = 0
192.168.1.251:444, SCA444, state = OPERATIONAL
  conns = 0, maxconns = 4294967295, minconns = 0
  weight = 8, weight(admin) = 8, metric = 0, remainder = 0
  total conns established = 0, total conn failures = 0

!--- This output shows that each web server has received a !--- connection. !--- The SCA .250 has received two connections, one to port 443 and !--- one to port 444. !--- The SCA .251 has not yet received any connection because !--- only two connections are open. One is open to each site !--- (10.10.10.10 and 10.10.10.20). A different port (443 or 444) !--- on the SCAs handles each site. The first !--- connection for each site goes to the first SCAs. !--- The following connection to either .10 or .20 goes to !--- .251, port 443 or 444, respectively. !--- This is SCA1 output.


!--- There is one open connection.

sca1# show netstat
Pro State Recv-Q Send-Q Local Address         Remote Address       
R-Win S-Win
---------------------------------------------------------------------------
tcp ESTAB      0      0 192.168.1.250:443     10.15.0.50:2324      
33580 16529
tcp ESTAB      0      0 192.168.1.250:4376    10.10.10.100:81      
33304 17232
udp            0      0 *:4099                *:*                      
0     0
udp            0      0 *:4098                *:*                      
0     0
tcp LISTN      0      0 *:2932                *:*                      
0     0
udp            0      0 *:2932                *:*                      
0     0
udp            0      0 *:520                 *:*                      
0     0
udp            0      0 *:514                 *:*                      
0     0
tcp LISTN      0      0 *:444                 *:*                      
0     0
tcp LISTN      0      0 *:443                 *:*                  
32768     0
tcp LISTN      0      0 *:80                  *:*                      
0     0
tcp LISTN      0      0 *:23                  *:*                      
0     0
sca1#

!--- There are two open connections.

sca1# show netstat
Pro State Recv-Q Send-Q Local Address         Remote Address       
R-Win S-Win
---------------------------------------------------------------------------
tcp ESTAB      0      0 192.168.1.250:444     10.15.0.50:2325      
33580 16529
tcp ESTAB      0      0 192.168.1.250:443     10.15.0.50:2324      
33580 16529
tcp ESTAB      0      0 192.168.1.250:4377    10.10.10.100:81      
33304 17232
tcp ESTAB      0      0 192.168.1.250:4376    10.10.10.100:81      
33304 17232
udp            0      0 *:4099                *:*                      
0     0
udp            0      0 *:4098                *:*                      
0     0
tcp LISTN      0      0 *:2932                *:*                      
0     0
udp            0      0 *:2932                *:*                      
0     0
udp            0      0 *:520                 *:*                      
0     0
udp            0      0 *:514                 *:*                      
0     0
tcp LISTN      0      0 *:444                 *:*                  
32768     0
tcp LISTN      0      0 *:443                 *:*                  
32768     0
tcp LISTN      0      0 *:80                  *:*                      
0     0
tcp LISTN      0      0 *:23                  *:*                      
0     0
sca1#

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

Revision History

Revision Publish Date Comments
1.0
11-Sep-2018
Initial Release

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