I have /28 16 ip addresses and then want to use them as my MX records. I have 2 real smtp servers that will send mail to outside and accept mail from outside while load balancing these 16 ips. I tried to do somethings with my own but outbound sending was unsuccessful. I created a virtual server with that my smtp servers can talk from port 25 and then created an snat pool with these ips connect it to this VS and I did not put any pool for the VS and it did not work. What should be the right config for this request in F5 LTM?

Not sure I understand about the 16 IPs but regardless, for the outbound you should use a separate wildcard VS (only enabled on the relevant internal VLAN) listening on port 25 and attach the SNAT Pool to that.

you mean you want to snat source ip to /28 16 ip addresses for outbound email from 2 smtp servers and accept inbound email destined to /28 16 ip addresses then load balance to 2 smtp servers, don't you?

yes, a virtual server with 16 ip address or 16 virtual server and 2 pool member to accept smtp incoming, I have succesfully achieved it. But I cannot achieve sending email. I defined an virtual server with ip address ie 192.168.0.3, my members servers are 192.168.0.4-5 and I put real 16 ips snat into 192.168.0.3 VS. but then I cannot figured it out how to redirect mail traffic to 192.168.0.3 port 25.

smtp outgoing load balancing

12 Replies

What_Lies_Bene1
Cirrostratus
Jun 05, 2014
Not sure I understand about the 16 IPs but regardless, for the outbound you should use a separate wildcard VS (only enabled on the relevant internal VLAN) listening on port 25 and attach the SNAT Pool to that.
nitass
Employee
Jun 05, 2014
you mean you want to snat source ip to /28 16 ip addresses for outbound email from 2 smtp servers and accept inbound email destined to /28 16 ip addresses then load balance to 2 smtp servers, don't you?
- edib_26117
  Nimbostratus
  Jun 05, 2014
  yes, a virtual server with 16 ip address or 16 virtual server and 2 pool member to accept smtp incoming, I have succesfully achieved it. But I cannot achieve sending email. I defined an virtual server with ip address ie 192.168.0.3, my members servers are 192.168.0.4-5 and I put real 16 ips snat into 192.168.0.3 VS. but then I cannot figured it out how to redirect mail traffic to 192.168.0.3 port 25.
nitass_89166
Noctilucent
Jun 05, 2014
you mean you want to snat source ip to /28 16 ip addresses for outbound email from 2 smtp servers and accept inbound email destined to /28 16 ip addresses then load balance to 2 smtp servers, don't you?
- edib_26117
  Nimbostratus
  Jun 05, 2014
  yes, a virtual server with 16 ip address or 16 virtual server and 2 pool member to accept smtp incoming, I have succesfully achieved it. But I cannot achieve sending email. I defined an virtual server with ip address ie 192.168.0.3, my members servers are 192.168.0.4-5 and I put real 16 ips snat into 192.168.0.3 VS. but then I cannot figured it out how to redirect mail traffic to 192.168.0.3 port 25.
nitass
Employee
Jun 05, 2014
I defined an virtual server with ip address ie 192.168.0.3, my members servers are 192.168.0.4-5 and I put real 16 ips snat into 192.168.0.3 VS. but then I cannot figured it out how to redirect mail traffic to 192.168.0.3 port 25.

as Steven mentioned, you should create wildcard forwarding virtual server listening on port 25 (0.0.0.0/0:25) and assign snatpool (/28 16 ip addresses) to it.
nitass
Employee
Jun 05, 2014
how can mail servers (pool members) route the mail traffik to this virtual server?

isn't smtp server default gateway bigip?
- edib_26117
  Nimbostratus
  Jun 05, 2014
  ok, I understand now. If I make default gateway of the members the bigip, then everything fits. At first without default gateway, I tried to solve it. but it seems that I must do that. thanks.
- What_Lies_Bene1
  Cirrostratus
  Jun 05, 2014
  Cool. Let us know if it works (or not).
nitass_89166
Noctilucent
Jun 05, 2014
how can mail servers (pool members) route the mail traffik to this virtual server?

isn't smtp server default gateway bigip?
- edib_26117
  Nimbostratus
  Jun 05, 2014
  ok, I understand now. If I make default gateway of the members the bigip, then everything fits. At first without default gateway, I tried to solve it. but it seems that I must do that. thanks.
- What_Lies_Bene1
  Cirrostratus
  Jun 05, 2014
  Cool. Let us know if it works (or not).

Forum Discussion

smtp outgoing load balancing

12 Replies

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