how to set A4 size by default (I have Letter now)

[Tomasz Chmielewski]

> (...)
>
> > > As I saw no web interface options for paper size, I tried setting
> > > "lpoptions -p printer -o media=A4", but it didn't help - printing a test
> > > page still means that the printer will error due to the lack of Letter
> > > paper.
> > >
> > > Any ideas?
> > Log into cups as admin. select printers, then modify printer. there should
> > be an option for page size.
>
> I'm pretty sure there is none to change the paper size.
> At least I didn't find any.
>
> I use CUPS 1.1.23.

What I mean, I get a "client-error-not-possible" error when trying to modify a printer.
I guess I have to configure the stuff once again.