iOS firewall

A dedicated firewall App for iOS/iPadOS doesn’t exist per-se. The need for no effective defences is a myth - perpetuated by those that do not fully understand risk to Information and device Security. Whilst iPad and iPhone are not at direct risk of malware infection in the traditional sense, there are many vulnerabilities to which they remain susceptible.

Now, to your explicit question...

If you are prepared to write a ruleset, it is possible to use a specialist App called DNSCloak to selectively filter your iPad/iPhone network connections. If you do a little research, you may find some preconfigured block-lists for you to use directly - or to use as a “seed” for your own block list and ruleset.

Using DNSCloak, you’ll also have the ability to flexibly configure and secure your DNS traffic (perhaps using DNSSEC, DoH and DoT protocols) - thus avoiding many of the potentially malicious or hostile redirect attacks that are endemic. I’ll discuss DNS in a little more detail shortly.

A further option that can be used standalone, or with DNSCloak, is use of one of the better Content Blocker Apps to mitigate Browser-based attacks - this being particularly valuable in providing a high degree of protection from both embedded browser and email content.

By far one of the very best and most respected within the Apple App Store - designed for iPad, iPhone and Mac - is 1Blocker for Safari.

https://apps.apple.com/gb/app/1blocker-for-safari/id1365531024

1Blocker is highly configurable - and crucially does not rely upon an external proxy-service of dubious provenance. All processing takes place on your device - and contrary to expectations, Safari will run faster and more efficiently.

Unwanted content is not simply filtered after download (a technique used by basic/inferior products), but instead undesirable embedded content blocked form download. A further benefit on metered services, such as cellular connections where you data may be capped or chargeable, this not only improves speed but also saves you money.

Use of a good Content Blocker will avoid a high proportion of otherwise inescapable risk when using your Safari browser, or linking to external sources from email. A high proportion of threat is effectively mitigated before it even reaches you.

A further measure to improve protection is to use a trusted Recursive DNS Service in preference to automatic DNS settings. This can either be set on a per-device basis in your device Settings, or can be set-up on your home Router. I strongly recommend using one of the following services - for which IPv4 and IPv6 server addresses are listed:

Quad9 (recommended)

9.9.9.9

149.112.112.112

2620:fe::fe

2620:fe::9

OpenDNS

208.67.222.222

208.67.220.220

2620:0:ccc::2

2620:0:ccd::2

Cloudflare+APNIC

1.1.1.1

1.0.0.1

2606:4700:4700::1111

2606:4700:4700::1001

Use of the above DNS services will help to shield you from “known bad” websites and URLs - and when used alongside 1Blocker, provides defense in depth. When coupled with DNSCloak, you can produce very effective “local” defences - that can actually improve the performance of your iPad.

I hope this information proves to be helpful.

Hello,

iPad’s security systems make it so that iPad does not need a separate firewall.

you don't need an extra firewall 1st of all, iPhones and iPads are 99.9% immune to viruses.