Load sharing NAT Server configuration example

As shown in Figure 65, three FTP servers are in the intranet to provide FTP services for external users. Configure NAT so that these external users use the address 202.38.1.1/16 to access the servers and the three FTP servers implement load sharing.

# Specify IP addresses for the interfaces on the router. (Details not shown.)

# Create NAT Server group 0, and add members to the group.

<Router> system-view
[Router] nat server-group 0
[Router-nat-server-group-0] inside ip 10.110.10.1 port 21
[Router-nat-server-group-0] inside ip 10.110.10.2 port 21
[Router-nat-server-group-0] inside ip 10.110.10.3 port 21
[Router-nat-server-group-0] quit

# Associate NAT Server group 0 with GigabitEthernet 1/0/2 so that servers in the server group can provide FTP services.

[Router] interface gigabitethernet 1/0/2
[Router-GigabitEthernet1/0/2] nat server protocol tcp global 202.38.1.1 ftp inside server-group 0

# Verify that external hosts can access the internal FTP server group. (Details not shown.)

# Display all NAT configuration and statistics.

[Router] display nat all
NAT server group information:
  Totally 1 NAT server groups.
  Group Number      Inside IP             Port    Weight
  0                 10.110.10.1           21      100
                    10.110.10.2           21      100
                    10.110.10.3           21      100

NAT internal server information:
  Totally 1 internal servers.
  Interface: GigabitEthernet1/0/2
    Protocol: 6(TCP)
    Global IP/port: 202.38.1.1/21
    Local IP/port : server group 0
                    10.110.10.1/21         (Connections: 1)
                    10.110.10.2/21         (Connections: 2)
                    10.110.10.3/21         (Connections: 2)
    Config status : Active

NAT logging:
  Log enable          : Disabled
  Flow-begin          : Disabled
  Flow-end            : Disabled
  Flow-active         : Disabled
  Port-block-assign   : Disabled
  Port-block-withdraw : Disabled
  Alarm               : Disabled

NAT mapping behavior:
  Mapping mode : Address and Port-Dependent
  ACL          : ---
  Config status: Active

NAT ALG:
  DNS        : Enabled
  FTP        : Enabled
  H323       : Enabled
  ICMP-ERROR : Enabled
  ILS        : Enabled
  MGCP       : Enabled
  NBT        : Enabled
  PPTP       : Enabled
  RSH        : Enabled
  RTSP       : Enabled
  SCCP       : Enabled
  SIP        : Enabled
  SQLNET     : Enabled
  TFTP       : Enabled
  XDMCP      : Enabled

# Display NAT session information generated when external hosts access an internal FTP server.

[Router] display nat session verbose
Initiator:
  Source      IP/port: 202.38.1.25/53957
  Destination IP/port: 202.38.1.1/21
  DS-Lite tunnel peer: -
  VPN instance/VLAN ID/Inline ID: -/-/-
  Protocol: TCP(6)
  Inbound interface: GigabitEthernet1/0/2
Responder:
  Source      IP/port: 10.110.10.3/21
  Destination IP/port: 202.38.1.25/53957
  DS-Lite tunnel peer: -
  VPN instance/VLAN ID/Inline ID: -/-/-
  Protocol: TCP(6)
  Inbound interface: GigabitEthernet1/0/1
State: TCP_ESTABLISHED
Application: FTP
Start time: 2012-08-16 11:06:07  TTL: 26s
Initiator->Responder:            1 packets         60 bytes
Responder->Initiator:            2 packets        120 bytes

Total sessions found: 5