Zero Downtime Upgrades on Cisco ASA Failover Pairs

Cisco ASA is still popular for many networks around the world. It’s well-known because of its strong firewall ability which includes L3/4 firewall filter, Intrusion Prevention, Antivirus, as well as VPN capability. For network and security redundancy, you may want to have more than one box of Cisco ASA and configure them as failover so that you can prevent network failure or outage when one box is down. On top of this, security holes may existing in the software part from time to time depending on ASA software you are running. As an example, on October 8, 2014, Cisco was critically announced about multiple vulnerabilities in Advisory ID cisco-sa-20141008-asa in Cisco ASA software which included Denial of Services of VPN, SQL*NET, IKEv2, DNS Inspection, SunRPC, etc. In this case, you are strongly recommended to upgrade your Cisco ASA software to later release which those problems have been fixed. Well, how can you do the upgrade without any interruption to your production network? Follow below instruction for the answer.

Upgrade Type

In this article, we provide you the step of ZERO downtime to upgrade your Cisco ASA software. Thus, there are three type of upgrading depending on release type of Cisco ASA software.

  • Maintenance Release Upgrade

You can upgrade directly from one maintenance release to another maintenance release within the same Minor release.

  • Minor Release Upgrade

In order to perform zero downtime upgrade, you have to upgrade from one minor release to the next minor release. Skipping a minor release is not support for zero-downtime. Example, you are running 7.0(1), you have to upgrade to 7.1(x) first before upgrading to 7.2(x).

  • Major Release upgrade

For Major release, you can only upgrade from last minor release of the previous version. For example, assuming 7.5 is the last minor release in 7.x version, then you can upgrade from 7.5 to 8.0.

Get Proper Software Version

This is necessary to get a proper software version for your Cisco ASA boxes. Without it, how can you do the upgrade, right? You can, of course, download the software from Cisco website if you have a valid contract. But what if you do not have?? Well, this is easy. You can send an email to [email protected] to request for a free upgrade. Dont worry, I also did this way to ask for software download before I compose this article.

Okay, now let move to the main part of the article. 🙂

Upgrading Cisco ASA Software

  • Verify Storage Space

First thing first, you have to check and verify the availability of storage space on your Cisco ASA so that you can upload the new software without any problem. We will also give away bonus to iNET9s’ readers about upgrading ASDM when we are at it in this article. Excited? 😀

CiscoASA# show flash: | include free
255426560 bytes total (89412176 bytes free)

As you can see from above output, I have about 89MB available. If you do not have enough space, remove some junks.

  • Transfer Software to Cisco ASA

Now let have a look below output from Cisco ASA for their current version of software and ASDM.

CiscoASA# show version | include image
System image file is “disk0:/asa821-k8.bin”
CiscoASA# show asdm image
Device Manager image file, disk0:/asdm-524.bin

Here is the information of my new software and ASDM along with IP of FTP server. You can use any method you want to transfer your software to Cisco ASA. In my case, I will use FTP.

  • FTP Server:
  • ASA Software: asa825-52-k8.bin
  • ASDM: asdm-733.bin

Let’s transfer ASA software first.

CiscoASA# copy ftp://seyma:[email protected]/asa825-52-k8.bin flash:

Address or name of remote host []?

Source username [seyma]?

Source password [password]?

Source filename [asa825-52-k8.bin]?

Destination filename [asa825-52-k8.bin]?

Accessing ftp://seyma:[email protected]/asa825-52-k8.bin…!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Writing file disk0:/asa825-52-k8.bin…!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
15464448 bytes copied in 21.750 secs (736402 bytes/sec)

Now transfer the ASDM.

CiscoASA# copy ftp://seyma:[email protected]/asdm-733.bin flash:

Address or name of remote host []?

Source username [seyma]?

Source password [password]?

Source filename [asdm-733.bin]?

Destination filename [asdm-733.bin]?

Accessing ftp://seyma:[email protected]/asdm-733.bin…!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Writing file disk0:/asdm-733.bin…!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
27289072 bytes copied in 41.60 secs (665587 bytes/sec)
  • Configure Cisco ASA to run new software

After you have successfully transferred both software and ASDM to your Cisco ASA, tell them which file to run.

CiscoASA# configure terminal
CiscoASA(config)# boot system flash:/asa825-52-k8.bin
INFO: Converting flash:/asa825-52-k8.bin to disk0:/asa825-52-k8.bin

CiscoASA(config)# asdm image flash:/asdm-7333.bin
CiscoASA(config)# exit
CiscoASA# copy running-config startup-config

Source filename [running-config]?
Cryptochecksum: 1661a7ce 88cbc54b a6d80f14 89fdc7ac

2735 bytes copied in 3.490 secs (911 bytes/sec)

Sweet! You have told your Cisco ASA to run new software now but it does not take affect yet until you reboot it.

  • Doing the Upgrade

So to avoid network interruption, issue below command on Active ASA to reload the Standby box.

CiscoASA# failover reload-standby

Wait few minutes for Standby box to reboot. When it comes back with the status “Standby ready”, please force the current Active state to the Standby by using below command.

CiscoASA# no failover active

You can use “show failover” to verify active/standby state. After the Standby holds the Active state, you can reboot the previous Active box with following command.

CiscoASA# reload

When it comes back, you can move back the Active state by using:

CiscoASA# failover active

Again, use “show failover” to verify Active/Standby state for ASA boxes.

That’s it!! You have now successfully upgraded Cisco ASA without any downtimes.

Cool? Drop us a comment or feedback.

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