[OpenAFS] using openafs client to server web pages
Mon, 17 Jul 2006 17:37:38 -0400
On Friday, July 14, 2006 05:19:46 PM -0700 David Bear <David.Bear@asu.edu>
> On Fri, Jul 14, 2006 at 07:21:35AM -0700, ted creedon wrote:
>> Look at the NetInfo file. Here Openafs looks at 10.1.1.193 as well as the
>> external IP address.
>> NetInfo would listen on all of:
> Yes, I've heard of the netinfo file. But I don't know where it is.
That's going to depend on how your bits were configured. In general, it's
going to be in the same place as the relevant CellServDB and ThisCell
files. Ted gave you an answer that would be correct if you were trying to
configure a fileserver built with Transarc-style paths, but you're
configuring an AFS client, not a server, and the OpenAFS packages for most
major Linux distributions use FHS-style paths.
Of course, the NetInfo file is also not the answer you're looking for. It
controls what addresses are advertised by a client or server, but not which
interfaces or addresses will be used to originate traffic -- that's
controlled by your operating system's network stack. In fact, it doesn't
even control on which interfaces you _receive_ traffic - Rx binds a socket
to INADDR_ANY and will accept traffic received on any interface.
There is an option (-rxbind) which changes this behavior, so that only the
single, specific interface identified by applying NetInfo and NetRestrict
will be used. With this option, Rx binds a socket to that single address,
so that only traffic destined to that address will be processed, and all
outbound traffic will originate from that address. This only works if,
after applying NetInfo and NetRestrict, there is _exactly one_ address
left. Otherwise, it has no effect.
But that wasn't your question. We'd save an awful lot of time and
confusion here if certain individuals would stop leading people on wild
goose chases with their wrong answers.
Your original question had to do with whether the OpenAFS client would talk
to the fileserver using a source address based on which virtual web server
receieved the request that resulted in trying to fetch a file. Russ gave
you the correct answer to this one, which is "no". When the web server
opens a file, the filesystem has no way to tell why it is opening the file,
let alone details about the origin of a request the server is processing.
The way to handle this is to grant the server machine access to all of the
files you want to serve from any of those virtual hosts, and then control
which pages are accessible from which virtual servers in the web server
If the web server had multiple _physical_ interfaces, you might want to
restrict it to using only one for AFS by using a combination of NetInfo and
the -rxbind switch. However, with _virtual_ interfaces, that's not
necessary - current OS's will always use the "real" address for outgoing
traffic, rather than one of the virtual ones. Of course, you could also
always just put multiple IP addresses into the group you're using.
Finally, let me make a plug for not using address-based ACL's. Besides
being terribly insecure, AFS IP-address-based ACL's are also quite flaky,
and some of the problems are not easily solved. If you're using AFS to
store static web pages which are accessible through a public web server,
why not just make the pages readable to system:anyuser and be done with it?
-- Jeffrey T. Hutzelman (N3NHS) <firstname.lastname@example.org>
Sr. Research Systems Programmer
School of Computer Science - Research Computing Facility
Carnegie Mellon University - Pittsburgh, PA