[LON-CAPA-admin] access server questions
Stefan Bisitz
st.bisitz at fh-wolfenbuettel.de
Thu Oct 16 02:32:28 EDT 2008
Hi Bob,
Your locally modified dns_hosts.tab file will be overwritten when you
install a new LON-CAPA release, but your old version will be
automatically saved in dns_hosts.tab.lpmsave in the same folder. You
will be warned about this change in the WARNINGS file which is always
generated in the install/update process.
Stefan Bisitz
On October 15, 2008 8:48 pm, Bob Gonzales wrote:
> Stuart,
>
> Hooray! It always good to know why/how things happened.
> Does an update always overwrite the dns_hosts.tab files (or
> any other important files)? Just asking since we will
> update to the latest release in the not too distant future.
>
> Thanks for all the effort that has gone into tracking this
> down!
>
> Bob Gonzales
> Binghamton University
> Chemistry Dept
>
> -----Original Message-----
> From: lon-capa-admin-admin at mail.lon-capa.org
> [mailto:lon-capa-admin-admin at mail.lon-capa.org] On Behalf Of Stuart
> RaeburnSent: Wednesday, October 15, 2008 12:08 PM
> To: lon-capa-admin at mail.lon-capa.org
> Subject: RE: [LON-CAPA-admin] access server questions
>
> Bob,
>
> I have identified the reason why you cannot see remote resources
> from
> your access server.
>
> Currently binghamtona2 is no longer included in the dns_hosts.tab
> file
> installed on one of the LON-CAPA DNS servers, because an update to
> LON-CAPA 2.7.1 (released 9/25) on that particular server on 10/6
> overwrote the more recent file (which included binghamtona2)
> previously installed on the server on 10/2. As a consequence other
>
> servers in the cluster will not permit connections if their hosts
> information (cached for 24 hours) was retrieved from this
> particular
> LON-CAPA DNS server.
>
> I have contacted the system administrator for the particular DNS
> server and requested an update to the dns_hosts.tab file. Assuming
>
> the DNS server is updated today, binghamtona2 should be able to see
>
> resources again after 5 am tomorrow, once cached hosts tables on
> remote servers have been refreshed.
>
> Stuart Raeburn
> MSU LON-CAPA group
>
>
> Quoting Bob Gonzales <rgonzal at binghamton.edu>:
>
> > Update: The IT guy looked at the firewall and found that the
> > library server had been removed from the list. So, he added it
> > back and we seem to be good. I can log into the Binghamton domain
> > from msu.
> >
> > However, I still cannot see remote resources from my access server.
> >
> > I got a note from Gerd about an update the dns tables for another
> > access server I am going to be installing. Here's part of what
> he sent:
> >
> >>
> >> Index: loncom/production_dns_hosts.tab diff -u
> >> loncom/production_dns_hosts.tab:1.47 loncom/
> >> production_dns_hosts.tab:1.48
> >> --- loncom/production_dns_hosts.tab:1.47 Thu Sep 25 23:15:14 2008
> >> +++ loncom/production_dns_hosts.tab Wed Oct 15 09:04:29 2008
> >> @@ -94,6 +94,7 @@
> >> ufml1:ufm:library:lon-capa-base1.server.uni-frankfurt.de:https
> >> binghamtonl1:binghamton:library:loncapa.chem.binghamton.edu
> >> binghamtona2:binghamton:access:loncapa2.chem.binghamton.edu
> >> +binghamtona3:binghamton:access:loncapa3.chem.binghamton.edu
> >> itul1:itu:library:www.fizikodev.itu.edu.tr
> >> uprml1:uprm:library:loncapa.hep.uprm.edu
> >> casel1:case:library:capa1.chem.cwru.edu
> >
> > Should I be able to see the access server that is already
> supposed to be
> > in the cluster, binghamtona2, in my local dns_hosts.tab files?
> Currently,> it doesn't appear in either my binghamtonl1 library
> server's file or the
> > binghamtona2 access server's file.
> >
> > Sorry if this is a dumb question or observation.
> >
> > Thanks,
> > Bob Gonzales
> > Binghamton University
> > Chemistry Dept
> >
> > -----Original Message-----
> > From: lon-capa-admin-admin at mail.lon-capa.org
> > [mailto:lon-capa-admin-admin at mail.lon-capa.org] On Behalf Of Stuart
> Raeburn
> > Sent: Tuesday, October 14, 2008 11:29 PM
> > To: lon-capa-admin at mail.lon-capa.org
> > Subject: RE: [LON-CAPA-admin] access server questions
> >
> > Bob,
> >
> > Curiously, it looks as though inbound traffic to port 5663 is being
> > blocked on your library server. nmap reports:
> >
> > Interesting ports on loncapa.chem.binghamton.edu (128.226.130.107):
> > PORT STATE SERVICE
> > 5663/tcp filtered unknown
> >
> > whereas port 5663 seems to open for inbound traffic on your
> access server:
> >
> > Interesting ports on loncapa2.chem.binghamton.edu (128.226.130.9):
> > PORT STATE SERVICE
> > 5663/tcp open unknown
> >
> > This is not consistent with the report that remote resources are
> > accessible on the library server but not on the access server.
> >
> > You should try in turn on each server to see if connection is
> possible> to the other server via port 5663.
> >
> > On 128.226.130.107
> > telnet 128.226.130.9 5663
> >
> > On: 128.226.130.9
> > telnet 128.226.130.107 5663
> >
> > You can also use:
> >
> > iptables --list
> >
> > to see whether the Fedora firewall is open for port 5663:
> >
> > e.g.,
> > ACCEPT tcp -- anywhere anywhere tcp
> dpt:5663>
> > Blocking inbound and/or outbound traffic may be occurring
> elsewhere in
> > the network.
> >
> > I am currently unable to start a session with a user in the msu
> domain> on either server.
> >
> > Stuart Raeburn
> > MSU LON-CAPA group
> >
> >
> > Quoting Bob Gonzales <rgonzal at binghamton.edu>:
> >
> >> lon-capa-admin at mail.lon-capa.org
> >>
> >> I made the changes outlined below, renaming my access server to
> >> what was entered in the loncapa DNS tables, and I was able to
> >> see remote resources in one of my homework sets from my access
> >> server. I only checked that one.
> >>
> >> Today, I went to check some other homework sets and I cannot see
> >> any of those remote resources (I get a message "Unable to Find...).
> >> I can still see the resources in the original set that I checked
> >> last week.
> >>
> >> On my library server I can see all the remote resources in all of
> >> my sets and I can browse to them via "Edit Course->Import".
> >>
> >> What can I check to help track down the problem?
> >>
> >> Thanks,
> >> Bob Gonzales
> >> Binghamton University
> >> Chemistry Dept
> >>
> >> -----Original Message-----
> >> From: lon-capa-admin-admin at mail.lon-capa.org
> >> [mailto:lon-capa-admin-admin at mail.lon-capa.org] On Behalf Of Stuart
> > Raeburn
> >> Sent: Saturday, October 04, 2008 5:14 PM
> >> To: lon-capa-admin at mail.lon-capa.org
> >> Subject: Re: [LON-CAPA-admin] access server questions
> >>
> >> Bob,
> >>
> >> Although the LON-CAPA cluster tables have been updated on the
> LON-CAPA
> >> "DNS" servers run by the LON-CAPA Academic Consortium, connections
> >> between your new server and other servers in the LON-CAPA
> network and
> >> are failing because there is a mismatch between the lonHostID
> used by
> >> your new server, and the lonHostID included in the record added
> to the
> >> hosts table on 9/26. This is the current entry in the
> dns_hosts.tab>> file:
> >>
> >> binghamtona2:binghamton:access:loncapa2.chem.binghamton.edu
> >>
> >> The login page for your new server reports:
> >> Domain: binghamton
> >> Server: binghamtona1 (access)
> >>
> >> The simplest thing would be for you to modify the lonHostID in:
> >> /etc/httpd/conf/loncapa.conf
> >>
> >> and the last line in /home/httpd/lonTabs/hosts.tab
> >> on loncapa2.chem.binghamton.edu
> >>
> >> so the new server is known as binghamtona2 everywhere.
> >>
> >> If you also added an entry for the access server to
> >> /home/httpd/lonTabs/hosts.tab on your library server
> >> (loncapa.chem.binghamton.edu)
> >> so the two servers could communicate with each other before the
> >> central dns_hosts tables had been updated you should modify that
> too.>> If you hadn't added a line to hosts.tab on your library
> server you can
> >> ignore this last part.
> >>
> >> You'll need to use:
> >>
> >> /etc/init.d/loncontrol restart
> >> /etc/init.d/httpd restart
> >>
> >> on your access server after you've made the change.
> >>
> >> The alternative to this would be to leave the entries on your own
> >> server(s) unchanged, and have the entry in the central DNS cluster
> >> tables changed to:
> >> binghamtona1:binghamton:access:loncapa2.chem.binghamton.edu.
> However,>> this will likely involve a greater delay because your
> server would
> >> only be able to connect to the network once the updated
> dns_hosts.tab>> file had been propagated to the LON-CAPA "DNS"
> servers at MSU, UIUC
> >> and SFU.
> >>
> >> I checked ports 80, 8080 and 5663 for inbound TCP/IP traffic to
> your>> new acces server. All looks good.
> >>
> >> loncapa2.chem.binghamton.edu (128.226.130.9):
> >> PORT STATE SERVICE
> >> 5663/tcp open unknown
> >> 8080/tcp open http-proxy
> >> 80/tcp open http
> >>
> >> Stuart Raeburn
> >> MSU LON-CAPA group
> >>
> >>
> >> Quoting Bob Gonzales <rgonzal at binghamton.edu>:
> >>
> >>> I've got a new access server in the domain. I've
> >>> been told it is in the cluster tables but it will
> >>> take a while to propagate around. It's been a week
> >>> now. How long does this usually take?
> >>>
> >>> When I log directly into the access server as a
> >>> course coordinator and go to edit contents
> >>> and go to import, I can see all of the domains but
> >>> clicking on a domain doesn't show me any resources,
> >>> it just turns the little arrow to point down without
> >>> showing anything from that domain.
> >>>
> >>> Likewise, if I log directly into the access server as
> >>> a student I can't see any of the resourses that are not
> >>> in my domain. For a composite page, wherever there is a
> >>> non-local resource I have the title of the resource displayed
> >>> and the words "Not available" displayed above it.
> >>>
> >>> My computer center has opened the 5663 and 80 for the
> >>> IP of the access server, 128.226.130.9, but if someone
> >>> would like to confirm that the ports are open for me that
> >>> might be helpful.
> >>>
> >>> Any other help would be appreciated, even if you just
> >>> tell me to be patient.
> >>>
> >>> Bob Gonzales
> >>> Binghamton University
> >>> Chemistry Dept
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> LON-CAPA-admin mailing list
> >>> LON-CAPA-admin at mail.lon-capa.org
> >>> http://mail.lon-capa.org/mailman/listinfo/lon-capa-admin
> >>>
> >
> >
>
>
>
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