Thanks for the replies. I changed the source to
deb ftp://security.debian.org/debian-security/ squeeze/updates main
with no difference, other than the error message now says:
Failed to fetch ftp://security.debian.org/debian-security/dists/squeeze/updates/main/binary-i386/Packages.gz Unable to fetch file, server said 'Failed to open file. ' [IP: 220.127.116.11 21]
I'm not sure what you mean by the forced proxy. It was my understanding that the file I've named proxy provides the username and password supplied to ftp sites, and can have any name. I'm not even sure where I got that information because it's been like this for several months. If I remove the file then I can not log into either site. With it I appear to be logging into both, but only reading one repository. From the error message I'm seeing I would say a path is misconfigured, but it sure looks OK to me now, after implementing your suggestion.
> Subject: Re: security updates using ftp
> From: firstname.lastname@example.org
> To: email@example.com
> CC: firstname.lastname@example.org
> Date: Tue, 30 Aug 2011 20:27:03 +0100
> On Tue, 2011-08-30 at 20:15 +0100, Adam D. Barratt wrote:
> > > Err ftp://security.debian.org squeeze/updates/main i386 Packages
> > > Unable to fetch file, server said 'Failed to open file. ' [IP:
> > > 18.104.22.168 21]
> > If you drop the forced proxy configuration, what happens?
> After a little experimentation, I suspect you'll get the same issue.
> Specifically, for FTP access, you want:
> deb ftp://security.debian.org/debian-security/ squeeze/updates main
> The shorter form works for HTTP because /dists/ is an alias
> for /debian-security/dists/; that's not the case for FTP.