Is it possible to use a WideIP to load balance connections to Mail Server (MX Records)
A customer implementation requires load balancing incoming connections to their hosted websites, that works ok. But the problem is with the mail, is it possible to configure F5 to load balance DNS responses between 2 MX records? And if not, what is the best way to load balance incoming mail connections (SMTP) not Web Mail. Thanks in advance
Listener order-of-precedence and SOL9038
I find myself confused on the wording of SOL9038 and appreciate any information that can clarify acutal LTM operation with respect to traffic that matches both a source and destination listener. The last line of SOL9038 states: "For example, a virtual server with a destination address and a netmask of 0.0.0.0/0:0 takes precedence over a source listener object." I understood this to mean that should traffic match both a source and destination listener, the destination listener would assume full control over the traffic and that the source listener would not take effect. My local SE seemed to be in agreement that, given a wildcard virtual of 0.0.0.0/0:*, traffic would never trigger a SNAT on the device. However I noted different operation in one of our production units. Home testing on LTM VE appears to show that the SNAT will take effect if the destination listener is not configured to SNAT traffic. So now I am reforming my understanding of SOL9038 to match what I've seen but want to confirm this is correct operation. The OOP allows both source and destination listeners to operate on the same traffic, but should a conflict arise the destination listener settings will take effect. More simply - source and destination listeners are NOT mutually exclusive? I can post information on testing conducted and results, but after reviewing the results and thinking it through the answer to my question my be as simple as the above. Thanks for any assistance! -Ed
GTM Listener IP - Best Practice
I'm looking for some clarification on this topic. I've seen it mentioned in various places (ex. http://support.f5.com/kb/en-us/solutions/public/5000/400/sol5427.html) that the best practice is to use one of the BIP-IPs self-IPs as the destination listener. "F5 recommends to always use a self IP address when defining a listener object for local name resolution. A listener object that is not defined as a self IP address cannot direct name resolution requests to BIND." I'm using v11.6 and have my listener assigned an IP on the same subnet as my external self-IP, but it's a different IP. Upon defining my listener in this manner, it automatically created an associated Virtual Server with the defined IP and everything works fine. What is the disadvantage in deploying a listener that doesn't use the same IP as one of the self-IPs on the system? I'm trying to understand why this is a best practice. I'd imagine an anycast deployment would also be deployed not using a self-IP of the system, but rather the listener would be assigned a /32 and then advertised by a routing protocol. Similar to using a loopback interface's address for deploying anycast on a router. Thanks, DaveiRule to resolve DNS for GTM (wide-ip if possible)
Hi I've server on cloud and want to try to use irule to resolve dynamic IP from cloud and return IP to user. I saw irule LTM can use RESOLVE:lookup and we can use it on Listener. But Is it possible to have the same function irule in wide-ip ? because if we attach irule on Listener, it will surely take more performance than wide-ip. Flow is When user send dns request for wide-ip "A" -> F5 resolve dynamic IP from cloud (it's hostname will be like ABCDEFG.cloud-us.com)-> F5 return IP to user. ps. due to some circumstance CNAME is not possible. Thank you
BigIP GTM/DNS - no listener?
I recently ran an ihealth report on one of our BigIP GTM servers in preparation for an upgrade from V11.x to 13. One of the warnings received was that "The BIG-IP GTM configuration is missing a listener object". I checked and indeed there are no listeners defined. That being said, the system is working correctly - and has been for a couple of years. The GTM (and its identical twin at another DC) is authoritative for several of our zones. It serves a mix of static IPs configured through ZoneRunner and WideIPs. There are no other (non-F5) DNS servers in the mix. I've read through (many) articles and documentation on configuring listeners and just can't see what I'm missing. Do I, in fact, need to add a listener to this device which is currently behaving as expected? If so, what is its purpose? Thanks
GTM Listener with pool
Hi, I was under impression that VS working as GTM Listener with DNS profile options: GSLB: Enabled Unhandled Query Actions: Allow and Pool assigned (with some backend DNS as member). when receiving request matching configured Wide IP will answer directly. From my test (v13.0.0HF2) it looks like it's not the case, request matching Wide IP is still send to pool member. Is that by design, bug or I made some mistake in configuration? Piotr
