[LON-CAPA-admin] Unable to see resources from uiuc domain

raeburn at msu.edu raeburn at msu.edu
Thu Feb 2 09:48:06 EST 2017


The problem here appears to be the SSL certificate installed on the  
UIUC library server.  If I run the command:

openssl s_client  -connect library1.lon-capa.uiuc.edu:443

The response includes:

verify error:num=20:unable to get local issuer certificate
verify error:num=27:certificate not trusted
verify error:num=21:unable to verify the first certificate

Because of this certificate problem you will be unable to view  
previously unreplicated resources in the uiuc domain on a LON-CAPA  
server running a Linux distro/version which includes perl-libwww-perl  
version 6.

That includes the binghamton LON-CAPA servers, but not the MSU  
LON-CAPA servers.

On a server with perl-libwww-perl version 6, you could implement a  
temporary workaround by modifying the repcopy() routine in  
/home/httpd/lib/perl/Apache/lonnet.pm to include this line:

$ua->ssl_opts( verify_hostname => 0 );

and then reload Apache.

> Is is somehow related to the ssl request on port 443?  I am not running ssl
> in the binghamton domain.  However, I can see resources on other domains
> (e.g. msu) that are running ssl.

Yes, it is related to the fact that the uiuc LON-CAPA library server  
is using https.

Other LON-CAPA servers also use https (including educog.com and  
s10.lite.msu.edu), and for those servers the openssl s_client command  
above does not report any errors, so this issue looks to be specific  
to the certificate on the uiuc LON-CAPA library server.

The fact that you do not use Apache/SSL for the binghamton LON-CAPA  
domain servers is not relevant here.  Although I would encourage you  
in the longer term to consider using Apache/SSL in the binghamton  
domain for security reasons.

letsencrypt.org has an automated process for obtaining SSL  
certificates to use with the Apache web server, at no cost.

Stuart Raeburn
LON-CAPA Academic Consortium

> Hi All,
> I've got a situation where none of my servers can view the actual resources
> from the uiuc domain.  They can all browse to any subdirectory and can look
> at the metadata for any resource.  But they can't see the contents of a
> resource file.  The window that shows the rendered resource does open but
> just has the one line "Unable to find SomeFileName.problem"  for problems
> and "Sorry! Resource not available." for images in it.
> For each resource that can't be viewed there is a line in lonnet.log like
> this:
> LWP get: 500 Can't connect to library1.lon-capa.uiuc.edu:443:
> /home/httpd/html/res/uiuc/cyerkes/Chem_102_/problems/Homework_4_QDB_8051158
> /LandingFieldArrival.jpg
> I had the network IT guy for the university look at the edge firewall logs
> and he could see my requests going out but he didn't see any answers coming
> back from the uiuc server.  He wasn't 100% sure that he logs everything
> coming in though so it's not definitive that they aren't coming back.
> Though the message above would lead one to think that uiuc is not replying
> or not getting my request.
> I can browse to and see resources in other domains.  I also logged into my
> course using a msu access server and was successful viewing uiuc
> resources.
> Entries in lonc.log and lond.log show that connections are being made and
> the fact that I can browse the subdirectorys says some things are OK.
> Is is somehow related to the ssl request on port 443?  I am not running ssl
> in the binghamton domain.  However, I can see resources on other domains
> (e.g. msu) that are running ssl.
> Using nmap against library1.lon-capa.uiuc.edu shows port 443 open.
> Thanks,
> Bob Gonzales
> Binghamton University

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