LB configuration on ACE

[12pratham]

I have  configured  2 SMTP Servers ,to balance traffic on port 25,and using source IP as sticky and doing a source nat .

And the algorithm is Round Robin

The traffic  from different mailservers need to hit my vip and balancer the traffic between the two servers.But instead all my the mailtraffic is going to only one SMTP server.

Please advise me on this if I need to change the sticky or add any thing to my configuration ,so that the traffic is LB equally between the 2SMTP servers.

probe smtp PROBE_SMTP

  interval 20

  passdetect interval 5

  passdetect count 2

  receive 1

  open 1

  expect status 211 250

rserver host SMTP1

  ip address 10.24.133.15

  inservice

rserver host SMTP2

  ip address 10.24.133.16

  inservice

serverfarm host SMTP

  probe PROBE_SMTP

  rserver SMTP1

    inservice

  rserver SMTP2

    inservice

sticky ip-netmask 255.255.255.255 address source SMTP_STICKY

  timeout 30

  replicate sticky

  serverfarm SMTP

class-map match-all SMTP_class

  2 match virtual-address 10.24.133.10 tcp eq

policy-map type loadbalance first-match SMTP_POLICY

  class class-default

    sticky-serverfarm SMTP_STICKY

policy-map multi-match POLICY

  class SMTP_class

    loadbalance vip inservice

    loadbalance policy SMTP_POLICY

    loadbalance vip icmp-reply active

    nat dynamic 2 vlan 10

[asharmav]

Hi Pratham,

The traffic is hitting a single rserver since you have ip sticky configured, so traffic from a particular mail server will always be going to a particular rserver.

Now if you remove sticky from your config, then traffic will be loadbalanced across both the rserver, however you will not have the mailserver go to the same smtp server everytime.

Please test your config with another mailserver ( different ip) , so that these requests will be going to another rserver.

Is there any specific reason you want to have sticky here ? if not you can go ahead and remove them.

Regards

Abijith

[12pratham]

Asharmav

The request to the VIP comes from various mailservers.But not sure why its not being LB equally between the 2SMTP servers

serverfarm     : SMTP, type: HOST

total rservers : 2

state          : ACTIVE

DWS state      : DISABLED

---------------------------------

                                                ----------connections-----------

       real                  weight state        current    total      failures

   ---+---------------------+------+------------+----------+----------+---------

   rserver: SMTP1

       10.24.133.15:0      8   OPERATIONAL     18         23772      968

   rserver: SMTP2

       10.24.133.16:0      8   OPERATIONAL     7          20664      1012

Please advise me if I need to change the sticky setting  or any other options

[asharmav]

Hi Pratham,

IP Sticky uses hashing algorithm to select the rserver, based on the Ip address , these hash values are associated each realserver on which we dont have control. Hence this is bound to lead to unequal loadbalance since the mail servers can have any ip adress and can fall into any hash group.

If you are looking for equal loadbalencing then you need to remove sticky or have a set of clients whose ip address can be divided into two groups equally, i presume this is not possible hence suggest you to remove sticky, if you are not in need of this feature.

Regards

Abijith