Sandwich Environment
A Citrix ADC deployment in a sandwich mode can load balance network traffic through firewalls in both directions: ingress (traffic entering the network from the outside, such as the internet) and egress (traffic leaving the network to the internet).
In this setup, a Citrix ADC is located on each side of a set of firewalls. The Citrix ADC placed between the firewalls and the Internet, called the external Citrix ADC that handles ingress traffic selects the best firewall, based on the configured method. The Citrix ADC between the firewalls and the private network, called the internal Citrix ADC tracks the firewall from which the initial packet for a session is received. It then makes sure that all subsequent packets for that session are sent to the same firewall.
The internal Citrix ADC can be configured as a regular traffic manager to load balance traffic across the private network servers. This configuration also allows traffic originating from the private network (egress) to be load balanced across the firewalls.
The following diagram shows the sandwich firewall load balancing environment.
Figure 1. Firewall Load Balancing (Sandwich)
The service type ANY configures the Citrix ADC to accept all traffic.
To avail benefits related to HTTP and TCP, configure the service and virtual server with type HTTP or TCP. For FTP to work, configure the service with type FTP.
Configuring the External Citrix ADC in a Sandwich Environment
Perform the following tasks to configure the external Citrix ADC in a sandwich environment
- Enable the load balancing feature.
- Configure a wildcard service for each firewall.
- Configure a monitor for each wildcard service.
- Configure a wildcard virtual server for traffic coming from the Internet.
- Configure the virtual server in MAC rewrite mode.
- Bind services to the wildcard virtual server.
- Save and Verify the Configuration.
Enable the load balancing feature
To enable load balancing by using the command line interface
At the command prompt, type the following command to enable load balancing and verify the configuration:
enable ns feature LB show ns feature Example:
> enable ns feature LoadBalancing Done > show ns feature Feature Acronym Status ------- ------- ------ 1) Web Logging WL OFF 2) Surge Protection SP ON 3) Load Balancing LB ON . . . 24) NetScaler Push push OFF Done To enable load balancing by using the configuration utility
Navigate toSystem > Settingsand, inConfigure Basic Features, selectLoad Balancing.
Configure a wildcard service for each firewall
To configure a wildcard service for each firewall by using the command line interface
At the command prompt, type:
add service ANY * Example:
add service Service-HTTP-1 10.102.29.5 ANY * To configure a wildcard service for each firewall by using the configuration utility
Navigate toTraffic Management > Load Balancing > Servicesand add a service. SpecifyANYin theProtocolfield and * in the Port field.
Configure a monitor for each wildcard service
A PING monitor is bound by default to the service. You need to configure a transparent monitor to monitor hosts on the trusted side through individual firewalls. You can then bind the transparent monitor to services. The default PING monitor monitors the connectivity only between the Citrix ADC appliance and the upstream device. The transparent monitor monitors all the devices existing in the path from the appliance to the device that owns the destination IP address specified in the monitor. If a transparent monitor is not configured and the status of the firewall is UP but one of the next hop devices from that firewall is down, the appliance includes the firewall while performing load balancing and forwards the packet to the firewall. However, the packet is not delivered to the final destination because one of the next hop devices is down. By binding a transparent monitor, if any of the devices (including the firewall) are down, the service is marked as DOWN and the firewall is not included when the appliance performs firewall load balancing.
Binding a transparent monitor overrides the PING monitor. To configure a PING monitor in addition to a transparent monitor, after you create and bind a transparent monitor, you need to bind a PING monitor to the service.
To configure a transparent monitor by using the command line interface
At the command prompt, type the following commands to configure a transparent monitor and verify the configuration:
add lb monitor [-destIP ] [-transparent (YES | NO )] bind lb monitor Example:
add monitor monitor-HTTP-1 HTTP -destip 10.10.10.11 -transparent YES bind monitor monitor-HTTP-1 fw-svc1 To bind a PING monitor, type the following command: bind monitor PING fw-svc1 To create and bind a transparent monitor by using the configuration utility
Navigate toTraffic Management > Load Balancing > Monitors, and then create and bind a transparent monitor.
Configure a wildcard virtual server for traffic coming from the Internet
To configure a wildcard virtual server for traffic coming from the Internet by using the command line interface
At the command prompt, type:
add lb vserver ANY * * Example:
add lb vserver Vserver-LB-1 ANY * * To configure a wildcard virtual server for traffic coming from the Internet by using the configuration utility
Navigate toTraffic Management > Load Balancing > Virtual Serversand create a wildcard virtual server. SpecifyANYin theProtocolfield and * in the Port field.
Configure the virtual server in MAC rewrite mode
To configure the virtual server in MAC rewrite mode by using the command line interface
At the command prompt, type:
set lb vserver @ -m Example:
set lb vserver Vserver-LB-1 -m MAC To configure the virtual server in MAC rewrite mode by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers, and select the virtual server for which you want to configure the redirection mode (for example, Vserver-LB-1).
- Edit theBasic Settingssection, and clickmore.
- From theRedirection Modedrop-down list, selectMAC Based.
Bind services to the wildcard virtual server
To bind a service to the wildcard virtual server by using the command line interface
At the command prompt, type:
bind lb vserver Example:
bind lb vserver Vserver-LB-1 Service-HTTP-1 To bind a service to the wildcard virtual server by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Serversand select the virtual server for which you want to bind the service.
- Click in theServicessection and select a service to bind.
Save and Verify the Configuration
When you’ve finished the configuration tasks, be sure to save the configuration. Ensure that the settings are correct.
To save and verify the configuration by using the command line interface
At the command prompt, type the following commands to configure a transparent monitor and verify the configuration:
保存ns配置show vserver Example:
保存配置sh磅vserver FWLBVIP1 FWLBVIP1 (*: *)- ANY Type: ADDRESS State: UP Last state change was at Mon Jun 14 06:40:14 2010 Time since last state change: 0 days, 00:00:11.240 Effective State: UP ARP:DISABLED Client Idle Timeout: 120 sec Down state flush: ENABLED Disable Primary Vserver On Down : DISABLED No. of Bound Services : 2 (Total) 2 (Active) Configured Method: SRCIPDESTIPHASH Mode: MAC Persistence: NONE Connection Failover: DISABLED 1) fw_svc_1 (10.102.29.251: *) - ANY State: UP Weight: 1 2) fw_svc_2 (10.102.29.18: *) - ANY State: UP Weight: 1 Done show service fw-svc1 fw-svc1 (10.102.29.251:*) - ANY State: DOWN Last state change was at Thu Jul 8 10:04:50 2010 Time since last state change: 0 days, 00:00:38.120 Server Name: 10.102.29.251 Server ID : 0 Monitor Threshold : 0 Max Conn: 0 Max Req: 0 Max Bandwidth: 0 kbits Use Source IP: NO Client Keepalive(CKA): NO Access Down Service: NO TCP Buffering(TCPB): YES HTTP Compression(CMP): NO Idle timeout: Client: 120 sec Server: 120 sec Client IP: DISABLED Cacheable: NO SC: OFF SP: OFF Down state flush: ENABLED 1) Monitor Name: monitor-HTTP-1 State: DOWN Weight: 1 Probes: 5 Failed [Total: 5 Current: 5] Last response: Failure - Time out during TCP connection establishment stage Response Time: 2000.0 millisec 2) Monitor Name: ping State: UP Weight: 1 Probes: 3 Failed [Total: 0 Current: 0] Last response: Success - ICMP echo reply received. Response Time: 1.415 millisec Done Configuring the Internal Citrix ADC in a Sandwich Environment
Perform the following tasks to configure the internal Citrix ADC in a sandwich environment
For traffic from the server (egress)
- Enable the load balancing feature.
- Configure a wildcard service for each firewall.
- Configure a monitor for each wildcard service.
- 配置一个虚拟服务器加载balanc通配符e the traffic sent to the firewalls.
- Configure the virtual server in MAC rewrite mode.
- Bind firewall services to the wildcard virtual server.
For traffic across private network servers
- Configure a service for each virtual server.
- Configure a monitor for each service.
- Configure an HTTP virtual server to balance traffic sent to the servers.
- Bind HTTP services to the HTTP virtual server.
- Save and Verify the Configuration.
Enable the load balancing feature
You can configure load balancing entities such as services and virtual servers when the load balancing feature is disabled. But they will not function until you enable the feature.
To enable load balancing by using the command line interface
At the command prompt, type the following command to enable load balancing and verify the configuration:
enable ns feature LB show ns feature Example:
> enable ns feature LoadBalancing Done > show ns feature Feature Acronym Status ------- ------- ------ 1) Web Logging WL OFF 2) Surge Protection SP ON 3) Load Balancing LB ON . . . 24) NetScaler Push push OFF Done To enable load balancing by using the configuration utility
Navigate toSystem > Settingsand, in Configure Basic Features, selectLoad Balancing.
Configure a wildcard service for each firewall
To configure a wildcard service for each firewall by using the command line interface
At the command prompt, type:
add service ANY * Example:
add service Service-HTTP-1 10.102.29.5 ANY * To configure a wildcard service for each firewall by using the configuration utility
Navigate toTraffic Management > Load Balancing > Servicesand add a service. SpecifyANYin theProtocolfield and * in the Port field.
Configure a monitor for each wildcard service
A PING monitor is bound by default to the service. You need to configure a transparent monitor to monitor hosts on the trusted side through individual firewalls. You can then bind the transparent monitor to services. The default PING monitor monitors the connectivity only between the Citrix ADC appliance and the upstream device. The transparent monitor monitors all the devices existing in the path from the appliance to the device that owns the destination IP address specified in the monitor. If a transparent monitor is not configured and the status of the firewall is UP but one of the next hop devices from that firewall is down, the appliance includes the firewall while performing load balancing and forwards the packet to the firewall. However, the packet is not delivered to the final destination because one of the next hop devices is down. By binding a transparent monitor, if any of the devices (including the firewall) are down, the service is marked as DOWN and the firewall is not included when the appliance performs firewall load balancing.
Binding a transparent monitor overrides the PING monitor. To configure a PING monitor in addition to a transparent monitor, after you create and bind a transparent monitor, you need to bind a PING monitor to the service.
To configure a transparent monitor by using the command line interface
At the command prompt, type the following commands to configure a transparent monitor and verify the configuration:
add lb monitor [-destIP ] [-transparent (YES | NO )] bind lb monitor Example:
add monitor monitor-HTTP-1 HTTP -destip 10.10.10.11 -transparent YES bind monitor monitor-HTTP-1 fw-svc1 To create and bind a transparent monitor by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Monitorsand create a monitor.
- In theCreate Monitordialog box, enter the required parameters, and selectTransparent.
配置一个虚拟服务器加载balanc通配符e the traffic sent to the firewalls
To configure a wildcard virtual server to load balance the traffic sent to the firewalls by using the command line interface
At the command prompt, type:
add lb vserver ANY * * Example:
add lb vserver Vserver-LB-1 ANY * * To configure a wildcard virtual server for traffic coming from the Internet by using the configuration utility
Navigate toTraffic Management > Load Balancing > Virtual Serversand create a wildcard virtual server.
SpecifyANYin the Protocol field and*in the Port field.
To configure a wildcard virtual server to load balance the traffic sent to the firewalls by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers.
- In the details pane, click Add.
- In the Create Virtual Server (Load Balancing) dialog box, specify values for the following parameters as shown:
- Name—name
- In Protocol, select ANY, and in IP Address and Port, select *.
- Click Create, and then click Close. The virtual server you created appears in the Load Balancing Virtual Servers pane.
Configure the virtual server in MAC rewrite mode
To configure the virtual server in MAC rewrite mode by using the command line interface
At the command prompt, type:
set lb vserver @ -m Example:
set lb vserver Vserver-LB-1 -m MAC To configure the virtual server in MAC rewrite mode by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers, and select the virtual server for which you want to configure the redirection mode (for example, Vserver-LB-1).
- Edit theBasic Settingssection, and clickmore.
- From theRedirection Modedrop-down list, selectMAC Based.
Bind firewall services to the wildcard virtual server
To bind firewall services to the wildcard virtual server by using the command line interface
At the command prompt, type:
bind lb vserver Example:
bind lb vserver Vserver-LB-1 Service-HTTP-1 To bind firewall services to the wildcard virtual server by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers, and select a virtual server.
- Click in the Service section, and select a service to bind.
Note: You can bind a service to multiple virtual servers.
Configure a service for each virtual server
To configure a service for each virtual server by using the command line interface
At the command prompt, type:
add service HTTP Example:
add service Service-HTTP-1 10.102.29.5 HTTP 80 To configure a service for each virtual server by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Services, and configure a service for each virtual server.
- SpecifyHTTPin theProtocolfield, and selectHTTPunderAvailable Monitors.
To configure a service for each virtual server by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Services.
- In the details pane, click Add.
- In the Create Service dialog box, specify values for the following parameters as shown:
- Service Name—name
- Server—serverName
- Port—port
- In Protocol, specify HTTP. Under Available Monitors, select HTTP.
- Click Create, and then click Close. The service you created appears in the Services pane.
Configure a monitor for each service
To bind a monitor to a service by using the command line interface
At the command prompt, type:
bind lb monitor Example:
bind mon monitor-HTTP-1 Service-HTTP-1 To bind a monitor to a service by using the configuration utility
Navigate toTraffic Management > Load Balancing > Services, double-click a service, and add a monitor.
Configure an HTTP virtual server to balance traffic sent to the servers
To configure an HTTP virtual server to balance traffic sent to the servers by using the command line interface
At the command prompt, type:
add lb vserver HTTP Example:
add lb vserver Vserver-LB-1 HTTP 10.102.29.60 80 To configure an HTTP virtual server to balance traffic sent to the servers by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Services, and configure an HTTP virtual server.
- SpecifyHTTPin theProtocolfield.
To configure an HTTP virtual server to balance traffic sent to the servers by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers.
- In the details pane, click Add.
- In the Create Virtual Server (Load Balancing) dialog box, specify values for the following parameters as shown:
- Name—name
- IP Address—IP Address Note: If the virtual server uses IPv6, select the IPv6 check box and enter the address in IPv6 format (for example,1000:0000:0000:0000:0005:0600:700a:888b).
- Port—port
- Under Protocol, select HTTP.
- Click Create, and then click Close. The virtual server you created appears in the Load Balancing Virtual Servers pane.
Save and Verify the Configuration
When you’ve finished the configuration tasks, be sure to save the configuration. You should also check to make sure that the settings are correct.
To save and verify the configuration by using the command line interface
At the command prompt, type the following commands to configure a transparent monitor and verify the configuration:
保存ns配置show vserver
Example:
save config show lb vserver FWLBVIP2 FWLBVIP2 (*:*) - ANY Type: ADDRESS State: UP Last state change was at Mon Jun 14 07:22:54 2010 Time since last state change: 0 days, 00:00:32.760 Effective State: UP Client Idle Timeout: 120 sec Down state flush: ENABLED Disable Primary Vserver On Down : DISABLED No. of Bound Services : 2 (Total) 2 (Active) Configured Method: LEASTCONNECTION Current Method: Round Robin, Reason: A new service is bound Mode: MAC Persistence: NONE Connection Failover: DISABLED 1) fw-int-svc1 (10.102.29.5: *) - ANY State: UP Weight: 1 2) fw-int-svc2 (10.102.29.9: *) - ANY State: UP Weight: 1 Done show service fw-int-svc1 fw-int-svc1 (10.102.29.5:*) - ANY State: DOWN Last state change was at Thu Jul 8 14:44:51 2010 Time since last state change: 0 days, 00:01:50.240 Server Name: 10.102.29.5 Server ID : 0 Monitor Threshold : 0 Max Conn: 0 Max Req: 0 Max Bandwidth: 0 kbits Use Source IP: NO Client Keepalive(CKA): NO Access Down Service: NO TCP Buffering(TCPB): NO HTTP Compression(CMP): NO Idle timeout: Client: 120 sec Server: 120 sec Client IP: DISABLED Cacheable: NO SC: OFF SP: OFF Down state flush: ENABLED 1) Monitor Name: monitor-HTTP-1 State: DOWN Weight: 1 Probes: 9 Failed [Total: 9 Current: 9] Last response: Failure - Time out during TCP connection establishment stage Response Time: 2000.0 millisec 2) Monitor Name: ping State: UP Weight: 1 Probes: 3 Failed [Total: 0 Current: 0] Last response: Success - ICMP echo reply received. Response Time: 1.275 millisec Done To save and verify the configuration by using the configuration utility
- In theDetailspane, clickSave.
- In theSave Configdialog box, clickYes.
- Navigate toTraffic Management > Load Balancing > Virtual Servers.
- In theDetailspane, select the virtual server that you created in step 5.
- Verify that the settings displayed in theDetailspane are correct.
- Navigate toTraffic Management > Load Balancing > Services.
- In theDetailspane, select the services that you created in step 5.
- Verify that the settings displayed in theDetailspane are correct.
Monitoring a Firewall Load Balancing Set up in a Sandwich Environment
After the configuration is up and running, you should view the statistics for each service and virtual server to check for possible problems.
Viewing the Statistics of a Virtual Server
To evaluate the performance of virtual servers or to troubleshoot problems, you can display details of the virtual servers configured on the Citrix ADC appliance. You can display a summary of statistics for all the virtual servers, or you can specify the name of a virtual server to display the statistics only for that virtual server. You can display the following details:
- Name
- IP address
- Port
- Protocol
- State of the virtual server
- Rate of requests received
- Rate of hits
To display virtual server statistics by using the command line interface
To display a summary of the statistics for all the virtual servers currently configured on the Citrix ADC, or for a single virtual server, at the command prompt, type:
stat lb vserver [-detail] [] Example:
>统计磅vserver细节虚拟服务器(s)总结vsvrIP port Protocol State Req/s Hits/s One * 80 HTTP UP 5/s 0/s Two * 0 TCP DOWN 0/s 0/s Three * 2598 TCP DOWN 0/s 0/s dnsVirtualNS 10.102.29.90 53 DNS DOWN 0/s 0/s BRVSERV 10.10.1.1 80 HTTP DOWN 0/s 0/s LBVIP 10.102.29.66 80 HTTP UP 0/s 0/s Done To display virtual server statistics by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Virtual Servers > Statistics.
- 如果你想要显示的数据只有一个virtual server, in the details pane, select the virtual server, and clickStatistics.
Viewing the Statistics of a Service
You can view the rate of requests, responses, request bytes, response bytes, current client connections, requests in surge queue, current server connections, and so forth using the service statistics.
To view the statistics of a service by using the command line interface
At the command prompt, type:
stat service Example:
stat service Service-HTTP-1 To view the statistics of a service by using the configuration utility
- Navigate toTraffic Management > Load Balancing > Services > Statistics.
- 如果你想要显示的数据只有一个service, select the service, and clickStatistics.