p.s. One thing I neglected to mention is the need to determine the site
addresses for content providers such as Syndetics, and to add them to the
system's local hosts file; otherwise, there will be missing content and
placeholders hither and yon.  Dealing with Google is a challenge, as I
can't very well whitelist google.com, but everyone is so fond of Google
analytics, fonts, APIs, etc, that sometimes it comes down to a trade-off
between a good experience/appearance and security.

John Lolis
Coordinator of Computer Systems

100 Martine Avenue
White Plains, NY  10601
tel: 1.914.422.1497
fax: 1.914.422.1452

https://whiteplainslibrary.org/

*“I would rather have questions that can’t be answered than answers that
can’t be questioned.”*
— Richard Feynman
<https://click.fourhourmail.com/5qure95xkf7hvvo93wh2/7qh7h8h05vr4zrtz/aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnL3dpa2kvUmljaGFyZF9GZXlubWFu>,
theoretical physicist and recipient of the Nobel Prize in Physics in 1965


On Mon, 26 Feb 2024 at 19:07, Lolis, John <[log in to unmask]> wrote:

> Wow.  Thanks so much, Kaleb.  I started looking into modifying that xhtml
> file, and found those waters I waded into to be quite deep.  I only got so
> far, but I came across mention of code signing that one would come across,
> and how that security makes it difficult to make modifications.  With my
> time being at such a premium these days, I decided to go with the more
> expedient solution, that is, to set up a proxy server with at least one
> custom error page.
>
> Since we already use pfSense here, it didn't take much to find the path to
> the Squid proxy error pages.  If anyone is interested, the English language
> ones can be found here (many more languages are available from up one
> level): /usr/local/etc/squid/errors/en
>
> Below is a quick-and-dirty page I came up with.  The file is
> /usr/local/etc/squid/errors/en/ERR_DNS_FAIL.  I thought of having an
> automatic redirect, but I think it's better to require some interaction.
>
> Thanks so much once again to everyone for their suggestions!
>
> [image: image.png]
>
>
> John Lolis
> Coordinator of Computer Systems
>
> 100 Martine Avenue
> White Plains, NY  10601
> tel: 1.914.422.1497
> fax: 1.914.422.1452
>
> https://whiteplainslibrary.org/
>
> *“I would rather have questions that can’t be answered than answers that
> can’t be questioned.”*
> — Richard Feynman
> <https://click.fourhourmail.com/5qure95xkf7hvvo93wh2/7qh7h8h05vr4zrtz/aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnL3dpa2kvUmljaGFyZF9GZXlubWFu>,
> theoretical physicist and recipient of the Nobel Prize in Physics in 1965
>
>
> On Thu, 8 Feb 2024 at 17:39, Sove67 <[log in to unmask]> wrote:
>
>> Hi John,
>>
>> Barring a more elegant solution, you could edit the .xhtml file that
>> Firefox redirects to when it reaches a net error (you can view this by
>> visiting the following "url" using firefox:
>> *about:neterror?e=dnsNotFound*).
>>
>> The accepted answer here
>> <
>> https://superuser.com/questions/1792996/customize-file-not-found-page-in-firefox-114
>> >
>> explains where to find that .xhtml file, inside the omni.ja archive.
>>
>> I've attached a custom omni.ja archive you could inject, and examples of
>> how it displays now vs how it used to display. If you plan to use this,
>> please save a copy of the original omni.ja file that you need to
>> overwrite!
>>  omni.ja
>> <
>> https://drive.google.com/file/d/1aExDyrFxdE0svkRZELAA2Zg03PHXtnwo/view?usp=drive_web
>> >
>> [image: Example.PNG]
>> [image: image.png]
>>
>> Best of luck,
>> Kaleb A. (Langara LIT Student)
>>
>> On Thu, Feb 8, 2024 at 1:10 PM Lolis, John <[log in to unmask]>
>> wrote:
>>
>> > Prithee, might one of you be able to point me in the right direction
>> with
>> > regard to modifying a browser error message, specifically a DNS
>> error/site
>> > not found message?
>> >
>> > Here's the rub... in an effort to prevent use of our OPACs as public
>> access
>> > computers, I've modified their DNS settings so that they only look to
>> > themselves for DNS queries.  In their hosts file, I only added entries
>> for
>> > our catalog, our website and our museum pass reservation site.
>> >
>> > So this effectively prevents access to all other sites (unless of course
>> > someone happens to know the IP address of another site).
>> >
>> > The problem is that the browser returns the DNS error/site not found
>> > message, and there are no browser controls to go back since it's in
>> kiosk
>> > mode.  We have a label advising patrons to press ALT← to go back to the
>> > previous page, but what I'd like to do is use a hex editor to modify the
>> > default browser error to communicate the same thing.
>> >
>> > So my question is, does anyone know where I can find those messages so I
>> > can edit them?  I've searched all sorts of Firefox files to no avail so
>> > far.  I'm not completely averse to using a different browser, although
>> my
>> > preference is to *not* use Chrome or Edge.
>> >
>> > I also realize that whatever string I replace the error message with, it
>> > must be the same length (this brings back memories of working at Prodigy
>> > and editing command.com in MS-DOS so that it would return Bad command,
>> you
>> > idiot!!).
>> >
>> > hmmm... as I write this, now I'm thinking of utilizing a redirect page
>> of
>> > some sort, one that displays advice to the patron, then returns to
>> > wherever.
>> >
>> > Thanks much!
>> >
>> > John Lolis
>> > Coordinator of Computer Systems
>> >
>> > 100 Martine Avenue
>> > White Plains, NY  10601
>> > tel: 1.914.422.1497
>> > fax: 1.914.422.1452
>> >
>> > https://whiteplainslibrary.org/
>> >
>> > *“I would rather have questions that can’t be answered than answers that
>> > can’t be questioned.”*
>> > — Richard Feynman
>> > <
>> >
>> https://click.fourhourmail.com/5qure95xkf7hvvo93wh2/7qh7h8h05vr4zrtz/aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnL3dpa2kvUmljaGFyZF9GZXlubWFu
>> > >,
>> > theoretical physicist and recipient of the Nobel Prize in Physics in
>> 1965
>> >
>>
>