syslog-ng to Azure Sentinel

23 May 2025

      I am dealing with the known Cisco bug for Excessive logging of "vpn:vpn [INFO] device" messages in /var/log/messages file.  It is filling our ingestion cap.  I have tried numerous ways to block this from being ingested but nothing has worked(adding filter and log).  Below is my syslog-ng.conf and I am looking for any advice to stop the "vpn:vpn [INFO] device" messages from being sent.  There are no syslog ids for this either so blocking it from FMC also isn't working

source s_sys {
    system();
    internal();
    # udp(ip(0.0.0.0) port(514));
};

destination d_cons { file("/dev/console"); };
destination d_mesg { file("/var/log/messages"); };
destination d_auth { file("/var/log/secure"); };
destination d_mail { file("/var/log/maillog" flush_lines(10)); };
destination d_spol { file("/var/log/spooler"); };
destination d_boot { file("/var/log/boot.log"); };
destination d_cron { file("/var/log/cron"); };
destination d_kern { file("/var/log/kern"); };
destination d_mlal { usertty("*"); };

filter f_kernel     { facility(kern); };
filter f_default    { level(info..emerg) and
                        not (facility(mail)
                        or facility(authpriv)
                        or facility(cron)); };
filter f_auth       { facility(authpriv); };
filter f_mail       { facility(mail); };
filter f_emergency  { level(emerg); };
filter f_news       { facility(uucp) or
                        (facility(news)
                        and level(crit..emerg)); };
filter f_boot   { facility(local7); };
filter f_cron   { facility(cron); };

#log { source(s_sys); filter(f_kernel); destination(d_cons); };
log { source(s_sys); filter(f_kernel); destination(d_kern); };
log { source(s_sys); filter(f_default); destination(d_mesg); };
log { source(s_sys); filter(f_auth); destination(d_auth); };
log { source(s_sys); filter(f_mail); destination(d_mail); };
log { source(s_sys); filter(f_emergency); destination(d_mlal); };
log { source(s_sys); filter(f_news); destination(d_spol); };
log { source(s_sys); filter(f_boot); destination(d_boot); };
log { source(s_sys); filter(f_cron); destination(d_cron); };

# Source additional configuration files (.conf extension only)
@include "/etc/syslog-ng/conf.d/*.conf"

# vim:ft=syslog-ng:ai:si:ts=4:sw=4:et:
#
#
source s_src { udp( port(514)); tcp( port(514));};

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Thank you.

David Jones

Steve Bernacki

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