Azure APPGW+WAF can be used to replace On-Perm IIS (ARR+NLB) during migration.

Question

Hi All,

We have a web farm with IIS (ARR + NLB) configured on-premises servers. Can we remove the IIS(ARR+NLB) layer and use Azure AppGW+WAF to route and Protect the web traffic when we migrated the servers to Azure?

Thanks & Regards,

Veera.

Answer 1

@Veera ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you are in the middle of migrating your OnPrem IIS servers to Azure.

I am not aware of the features provided by ARR+NLB layer, however, I can list the features available at Application Gateway and WAF.

App Gateway:

• Azure Application Gateway is a web traffic (OSI layer 7) load balancer that enables you to manage traffic to your web applications. More like a reverse proxy.
• You can add VMs in Azure to the backend pool of App gateway, this means you can add IIS Servers without an issue.
• See : Backend pools

App Gateway WAF:

• See : What is Azure Web Application Firewall on Azure Application Gateway
• WAF on Application Gateway is based on the Core Rule Set (CRS) from the Open Web Application Security Project (OWASP).
• Features : https://learn.microsoft.com/en-us/azure/web-application-firewall/ag/ag-overview#features
• In addition to the above, it lets you create Custom rules and includes Bot protection rule set
• Please note that you should Tune your WAF according to your requirements/environment should you feel you are facing a large number of false positives.
• You may do it by
  1.Creating exclusions
  2.Creating custom WAF rules
  3.or Disabling the Rule ID matched

Should you have any specific feature requirement, please do let us know and I shall confirm if it is available in WAF or not.

Hope this helps.

Thanks,

Kapil

Answer 2

Hi,

Yes, absolutely. Application Gateway was similar to ARR which act as a reverse proxy. When you move your web servers to Azure, you will be able to use Application Gateway instead of ARR.

Regards,

Karthik Srinivas