[lvs-users] Help with LVS NAT and RHEL5.8

[Liu, William]

Hi,

I am a problem with LVS NAT configuration where the packets do not look like they are being masqueraded by LVS.   Here's my setup:

LVS server has 3 interfaces: primary, nat_router, virtual IP
172.5.111.74 -primary
172.25.117.4 - nat router
172.25.117.5 - virtual IP, port 80
                |---- 172.28.12.56 (Real server)

A client (172.25.111.8) connects to 172.25.117.5 on port 80 never gets a response back.  What I see on Real sever (172.28.12.56) on tcpdump is :
16:35:08.103968 IP 172.25.111.8.34271 > 172.28.12.56.http: S 1718115488:1718115488(0) win 5840 <mss 1460,sackOK,timestamp 500867550 0,nop,wscale 7>

This shows source IP of the client and NOT from LVS.  I presume in NAT mode, the source IP should be of the "nat router?"  From my understanding LVS should have done the header masquerading?  I shouldn't have to use IPtables?  Please let me know what I have to do for this function to work?

# ipvsadm -l -n --stats
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port               Conns   InPkts  OutPkts  InBytes OutBytes
  -> RemoteAddress:Port
TCP  172.25.117.5:80                     4       15        0      900        0
  -> 172.28.12.56:80                     4       15        0      900        0

I would like LVS server to be the gateway for both traffic to the real server and on the way back to the client.

This LVS server is a RHEL5.8 with 2.6.18 kernel.  Here is my lvs.cf config:
serial_no = 16
primary = 172.25.111.74
service = lvs
backup = 0.0.0.0
heartbeat = 1
heartbeat_port = 539
keepalive = 6
deadtime = 18
network = nat
nat_router = 172.25.117.4 eth1:1
nat_nmask = 255.255.255.0
debug_level = NONE
virtual 172.28.12.56 {
     active = 1
     address = 172.25.117.5 eth1:2
     vip_nmask = 255.255.255.255
     port = 80
     expect = "OK"
     use_regex = 0
     send_program = "/etc/sysconfig/ha/check_tcp80.sh %h"
     load_monitor = none
     scheduler = rr
     protocol = tcp
     timeout = 60
     reentry = 15
     quiesce_server = 0
     server diadm1cm {
         address = 172.28.12.56
         active = 1
         weight = 1
     }
}

________________________________
This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster at nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes.
To protect the environment please do not print this e-mail unless necessary.

An NDS Group Limited company. www.nds.com