Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

Cisco Employee

SA520 or SA540 can do ADSL load balancing?


A partner in Italy asked for a firewall solution that supports:

1. 50 users
2. If possible, able to do a Load Balance with 3 ADSL

I've recommended the ASA 5500, but then they would need a router for the ADSL load balancing.

Now, he asked me if the SA520 or SA540 will be able to do the same?

Can SA520 or SA540 be able to do ADSL load balancing, or will he still need a router to do LB?

Thanks in advance for your help.

- Rika

Everyone's tags (3)
New Member

Re: SA520 or SA540 can do ADSL load balancing?

Hello Rika,

The SA500 series does support load balancing for up to two WAN connections on the Dedicated and Optional WAN ports. Make sure you configure both WAN ports with the Connectivity Type set to Keep Connection. If the WAN times out, load balancing isn't effective.

There is also the option of "protocol binding," wherein you can specify services (by default there are some services already included by default, or you can designate you own based on port number), and then "bind" those services to only travel on a specific WAN port, to further control the traffic.

Thank you,


New Member

SA520 or SA540 can do ADSL load balancing?

Further to the OP, If I may request a bit more info regarding a problem I have.

I have configured my SA520 like this:

WAN - naked ADSL cct, just static IP address configured

Optional port - PPPOE ADSL cct with static IP

Optional port load balancing with NO failure detection selected

Protocol bindings : SMTP to dedicated WAN, HTTP & HTTPS to Optional port

My issue is this:  I can check my HTTP IP using and it will usually sho the IP for the optional port. However occasionally it will show the IP for the dedicated wan port. This isn't a great issue for HTTP but it seems that SMTP is also being swapped over. This is an issue as I cannot receive mail at these times

I also have a bandwidth profile set to the dedicated wan port for SMTP to rate limit the outgoing SMTP traffic to low priority

My question is how and why is the traffic being swapped over and how can I stop it from happening?

If there a way to see what the current status is, eg thru SNMP messages?

Cisco Employee

SA520 or SA540 can do ADSL load balancing?


First, please upgrade to the latest image MR4, RC1

Second, please take a look of this posting, let me know if it helps

If none of those helps, Please contact the SBSC team to help you resolve this. 

Their phone number is:1-866-606-1866. The following page contains the pertinent contact list.



Re: SA520 or SA540 can do ADSL load balancing?

SA5xx dont have ADSL interfaces.  They have one optional port that can be used as a second WAN for load balance or fail over.  They can both handle 50 users.