[Xymon] I need help troubleshooting a xymon issue

Timothy Williams tlwilliams4 at vcu.edu
Wed Jul 31 17:35:08 CEST 2019


You did not specify what OS and client this pertains to. On the assumption
it is Windows using the powershell client, the second issue was fixed after
about version 2.28 by a client-local keyword of PORTS:listenonly which
limits the ports information to only the listening ports; all of the
'established' info is discarded. This cuts the size of the data file down a
lot.

We are also dealing with the first issue of invalid SSL connections on the
HTTP tests for some servers. My observation of the underlying ciphers on
the affected servers is that they were recently security-tightened to only
include "forward-secrecy" ciphers, and I think that the Xymon server can't
handshake using only those. Successful handshakes are
using ECDHE-RSA-AES256-GCM-SHA384, while failing
have ECDHE_RSA_WITH_AES_256_CBC_SHA384 (only the CBC variant).

Tim Williams
VCU Computing Center


On Wed, Jul 31, 2019 at 11:22 AM Adam Thorn <alt36 at cam.ac.uk> wrote:

> On 31/07/2019 13:00, David Hickenbottom wrote:
> > Hi,
> >
> > First of all Thank You!  This is a fantastic product.  I have two
> > problems.  The first is with regards to SSL monitoring.  I have a group
> > of 20 or so webservers.  Half monitor the SSL certificate correctly, the
> > others act like they do not see one.
> >
> > It looks good from every way I can look at it, but Xymon is not happy!
> > Is there a way for me to see what is going on?
> Bit of a guess here: do you need to use SNI
> (https://en.wikipedia.org/wiki/Server_Name_Indication) for the hosts
> where the test fails? Assuming this is the built in sslcert test
> performed by xymonnet, you can run it yourself with e.g.
>
> /usr/lib/xymon/server/bin/xymonnet pr26.imbills.com --noping --no-update
>
> where --no-update will print the test output to stdout rather than
> reporting to your xymon server. (NB that'll run all the xymonnet tests,
> not just sslcert) If you need SNI, you can add --sni=on to that command
> as a test, and/or add "sni" to the relevant line in hosts.cfg.
>
> You can also add --debug to the above xymonnet command, which might or
> might not give you information about the failure.
>
> Adam
> _______________________________________________
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> Xymon at xymon.com
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>
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