Understanding Inbound Load Balancing

Inbound Load Balancing distributes inbound data traffic over multiple WAN links to computers/servers behind Peplink Balance. Peplink Balance 210, 310, 305, 380, 580, 710, and 1350 have a built-in DNS server that enables this functionality.

Built-in DNS server functionality is not available on Peplink Balance 20 and 30.

Inbound Load Balancing is configured via both of the following:

The following is a simplified example of an Inbound Load Balancing scenario when Peplink Balance is acting as an authoritative DNS server, further details subsequently follow:
  1. Peplink Balance is being an authoritative DNS server of domain foobar.com
  2. The web server that serves foobar.com is housed behind Peplink Balance, where Peplink Balance distributes the web server's data traffic across two WAN links (i.e. WAN1 and WAN2).


Both WANs are avaliable and traffic are load balanced.
In further detail, with the aforementioned DNS records, the following steps take place when resolving the hostname foobar.com:
  1. A client computer requires resolution for foobar.com, and queries the build-in DNS server of Peplink Balance for foobar.com
  2. The client computer queries, via WAN1, the DNS of Peplink Balance for the resolution of foobar.com. In the event that the WAN1 connection is down, the DNS query would not succeed. However, as a built-in mechanism of the DNS protocol, the client computer then queries via WAN2 to resolve the hostname foobar.com
  3. Peplink Balance, upon receiving the DNS query, returns to the client computer the IP addresses of foobar.com that correspond to available WAN links. For example:
    • If both WAN1 and WAN2 are available, then both the IP address that corresponds to WAN1 and that of WAN2 are returned.
    • If WAN1 is available but WAN2 is down, then the IP address that corresponds to WAN1 is returned, but that of WAN2 is not returned.


WAN1 is down and incoming traffic goes through WAN2.


Thanks Peplink team for posting these feature summaries. They are very helpful.

Just out of curiosity, since I only have a balance 30 - are there different inbound balancing algorithms? Or is it always based on WAN link status?

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Inbound load balancing requires the Authoritative DNS feature and this is not available on the Balance 30.



I understand that this option is not available on my router. I was curious as to what types of inbound load balancing algorithms are available for those with the option available to them. Round Robin? Weighted balance? Enforced? Persistent? Etc.

It looked like you were describing a feature and I was inquiring about capabilities of that feature. It is cool technology and I would like to know more.


Sure thing! Inbound load balancing uses a Round Robin algorithm for the configured WAN connections. You can also choose to have a WAN as primary and only failover to a different WAN if it fails. Thanks!


Thanks! Keep up the great work. I love features and logs and cool stuff!

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Hi, I’m looking to purchase PepLink Load Balance. But I have the below scenario.
ISP A - using fixed IP
ISP B - using dynamic IP

Question is how do I achieve Inbound Load Balance with the above.

Please advise if it’s doable.

Thanks & Regards.

Inbound load balancing using Authoritative DNS requires a static IP on each ISP connection. Thanks


Hi, I’m using Peplink Balance 710 as the DNS server in my organisation. I have setup three WAN connections with inbound Load Balancing, but the issue i’m facing is whenever a WAN connection goes down new requests coming to DNS server will give a delay of 30 Seconds before routing it to the alternate WAN connection. All my WAN connections are in “Always-on” and same priority. Please let me know how to overcome this issue.


Please open a support ticket to allow support team to further check on the 30 seconds delay issue.


Hi, I got DNS Server, Web Server under load balancer and I got 2 ISP Link. how to configure bounding DNS Server and Web Server.

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Can you please help me understand the inbound load balancing?

  1. My scenario is this: I have a location in a rural area that can be served by different ISPs using different technologies such as DSL via hardwired phone lines and Satellite. Both providers are not that fast particularly. Would the inbound load balancing actually allow the same computer to use both ISPs at the same time, thereby giving it increased bandwidth? Or does it merely alternate between them? Or favor the provider with the fasted inbound speed? etc.

  2. Since we’re talking about “inbound” load balancing, what (if any) benefit would a computer have in this scenario on upload speeds?. Upload speeds in rural Internet connections are painstakingly slow, so would any of the Peplink devices be able to use both ISPs to also increase outbound bandwidth?

As you can probably see, I’m looking a way to increase overall bandwidth while having redundancy, but I would prefer not to have one ISP connection “idle” untl needed. This may not be possible. That’s why I am asking.


@jessem Hi and welcome to the forum!

Inbound load balancing is specifically for when you want to provide access to a thing (a web server, a cctv system etc) from the internet using multiple WAN links.

What you’re asking about is the more traditional multi WAN load balancing techniques.

I wrote an article an age ago about why its clever and easy which you might find of use.

Happy to walk you through the options but suggest you start a new thread to keep things tidy.


Hi, i have a question with the dns feature. I am used with f5 gtm where gtm can actually monitor the service port is its up before returning the a record to users. For example, if both wan link up, but one of the service port of the backend server in one dc is down, i shouldn’t give the record from that dc. On gtm this is achieved by port monitoring. In peplink, i dont this capability. Meaning it can balance wan monitoring but can guarantee to feasibility of backend server functionality. Please advice as customer is having issues migrating from gtm to peplink.

Peplink manages inbound WAN monitoring (Layer3) but does not test the health of LAN side services.
F5 or Kemp load balancer is still required for application level service monitoring.