No. Apps can only modify files within the documents directory, within their own sandbox. This is for security, and ease of installing/uninstalling. So you could only do this on a jailbroken device.

The previous answer is correct, but if the effect you are looking for is to redirect HTTP traffic for a domain to another IP there is a way.

Since it technically is not answering your question, I have asked and answered the question here:

How can I redirect HTTP requests made from an iPad?

The easiest way to do this is to run an iPad simulator using XCode and then add an entry in the hosts file (/etc/hosts) on the host system to point to your test site.

I would imagine you could do it by setting up a transparent proxy, using something like charles and re-direct traffic that way

Yes, you can edit the iPad hosts file, but you need to be jailbroken. Once you've done that, download Cydia (app market), and get iFile. The hosts file is located within "/etc/hosts".

If you have the freedom to choose the hostname, then you can just add your host to a dynanmic DNS service, like dyndns.org. Then you can rely on the iPad's normal resolution mechanisms to resolve the address.

Workarond I use for development purposes:

1. Create your own proxy server (One option would be: Squid on Linux).
2. Set your hosts file with your domains.
3. Set the proxy server on the IPAD/IPHONE and you can use with your hosts.

You can also make use of a proxy server on your iPhone or iPade via mobile internet (3G) by using a iPhone Mobile proxy generator:

http://iphonesettings.net/mobileproxygenerator.php

Just enter the apn of your carrier (with apn username/password if needed) and the proxy server you want to go through and tap Generate

No, you can't change iPad's host file(without jailbreak), but can workaround.

Here is my scenario:

• Mac OS X, with IP 192.168.2.1, running a web app
• iPad, the device you would like to test the web app
• Charles (for Mac), enables HTTP proxy for your iPad

I am going to test the web app running in my Mac via iPad, but I can't access directly to it.

The solution works for me:

• Firstly, make sure that your server and iPad are in the same local network.
• Then, set up Charles proxy, in the menu "Proxy > Proxy Settings...", fill in Port(mostly 8888) and toggle Enable transparent HTTP proxying.

• Setup proxy setting in iPad.

Now you can visit your web app in iPad.

Of course you can use other proxy tools like Squid or Varnish in Linux, or fiddler in Wondows.

I know it's been a while this has been posted, but with iOS 7.1, a few things have changed.

So far, if you are developing an App, you MUST have a valid SSL certificate recognized by Apple, otherwise you will get an error message on you iDevice. No more self-signed certificates. See here a list:

http://support.apple.com/kb/ht5012

Additionally, if you are here, it means that you are trying to make you iDevice resolve a name (to your https server), on a test or development environment.

Instead of using squid, which is a great application, you could simply run a very basic DNS server like dnsmasq. It will use your hosts file as a first line of name resolution, so, you can basically fool your iDevice there, saying that www.blah.com is 192.168.10.10.

The configuration file is as simple as 3 to 4 lines, and you can even configure its internal DHCP server if you want.

Here is mine:

listen-address=192.168.10.35

domain-needed

bogus-priv

no-dhcp-interface=eth0

local=/localnet/

Of course you have to configure networking on your iDevice to use that DNS (192.168.10.35 in my case), or just start using DHCP from that server anyway, after properly configured.

Additionally, if dnsmasq cannot resolve the name internally, it uses your regular DNS server (like 8.8.8.8) to resolve it for you. VERY simple, elegant, and solved my problems with iDevice App installation in-house.

By the way, solves many name resolution problems with regular macs (OS X) as well.

Now, my rant: bloody Apple. Making a device safe should not include castrating the operating system or the developers.

I needed the same functionality, and doing jailbreak is no-no. One solution is to host yourself DNS server (MaraDNS), go to your wifi settings in ipad/phone, and add your custom DNS server there.

The whole process took me only 10 minutes, and it works!

1) Download MaraDNS

2) Run mkSecretTxt.exe as administrator

3) Modify mararc file, mine is:

ipv4_bind_addresses = "put your public IP Here"
timestamp_type = 2
random_seed_file = "secret.txt"


csv2 = {}
csv2["Simple.Example.com."] = "example.configuration"

Add file called "example.configuration" into the same folder where run_maradns.bat is.

4) Edit your example.configuration file:

Simple.Example.com. 10.10.13.13 ~

5) Disable all Firewalls (convenience)

6) Run file "run_maradns.bat"

7) There should be no errors.

8) Add your DNS server to list, as shown here: http://www.iphonehacks.com/2014/08/change-dns-iphone-ipad.html

9) Works!

You need access to /private/etc/ so, no. you cant.

Best Answer: Simply add http or https in your browser, the IP address, colon and port number. Example: https://123.23.145.67:80

Problem Restated: Bypassing DNS Resolution

The problem the OP is trying to solve is NOT hacking hosts files on iPads per se, but rather bypassing DNS Resolution of a specific published DNS record by creating a static, local IP:name mapping on their device.

Solution:

A better- and more scalable- way is to create the static IP:Name mapping that you'd create in the hosts file on the device and instead create it on the router and then point your DHCP addressed clients to that router as the primary source of DNS resolution as I document (with annotated screen shots) HERE.

Conclusion:

When testing a new site you need to check the display of it on multiple devices to ensure there's no funky display or usability issues. Bypassing DNS checking using static local IP:Name mappings would require each developer to hack the hosts files for each of their devices and then remember to unwind the changes in all their devices after testing.

And were it even possible to hack an iPad's hosts file as the OP enquired about, in many organizations the Developers IT assets will be locked-down and they won't they have administrative permissions to do such tinkering.

Better to make the static mapping to bypass the published DNS record in the router and then you can delete it in one place after testing is completed.