Simple effective syslog server

While I used to install php-syslog-ng (now called Logzilla) I now just use the most simple setup for a syslog server. It looks nice to have a gui but logging everything to mysql is a huge bottleneck for performance. So I rebuild a syslog server which simply logs everything to files. A gui is nice but not nearly as powerful as the command line.

This is install was done on Debian Lenny but should work on any distribution which distributes syslog-ng.

apt-get install syslog-ng apache2

edit /etc/syslog-ng/syslog-ng.conf. What needs to be added is logging through udp and logging to per host files. This is done by the following entries in the config:

#Amongst others these are important options
options {
  ...
  create_dirs(yes);
  dir_perm(0755);
  ...
}
#All message received through the network
source s_remote {
  udp();
};
#every host gets it's own file per day.
#I give the www-data group permission so the webserver can access the files
destination df_host {
  file("/var/www/$HOST/$MONTH-$DAY.log"
  group("www-data")
  template("$YEAR-$MONTH-$DAY $PROGRAM $FACILITY $LEVEL $PRIORITY $MSG\n")  );
};
#log source to destination
log {
  source(s_remote_all);
  destination(df_host);
};

My complete syslog-ng.conf can be found at the bottom of this page:

Although I advice everybody to just learn the command line I cannot get around the lazy admin who just wants to click through things. So to give them some options I just serve all the log files through Apache. Since I log everything to /var/www/ it works out of the box. (on Debian) You only need to remove the index.html

rm /var/www/index.html

However security is a concern with a log archive. I just enable ldap authentication so only authenticated/authorized users can access the files. This is accomplished by changing the default site file in apache.

in /etc/apache2/sites-available/default add and customise for your setup:

<Directory /var/www/>
       Options +FollowSymLinks
       AuthType Basic
       AuthBasicProvider ldap
       AuthName "Paspoort Login"
       AuthLDAPURL ldaps://ldap.your.org:636/ou=users,o=org?cn
       AuthLDAPBindDN cn=admin,o=org
       AuthLDAPBindPassword "secret"
       Require valid-user
       AllowOverride None
       order deny,allow
       deny from all
       allow from 127.0.0.1
       satisfy any
    </Directory>

Please note this is not a secure setup since the authentication is plaintext. If you want this to be most secure you'll need to https!

Complete syslog-ng.conf

#
# Configuration file for syslog-ng under Debian
#
# attempts at reproducing default syslog behavior

# the standard syslog levels are (in descending order of priority):
# emerg alert crit err warning notice info debug
# the aliases "error", "panic", and "warn" are deprecated
# the "none" priority found in the original syslogd configuration is
# only used in internal messages created by syslogd

######
# options

options {
        # disable the chained hostname format in logs
        # (default is enabled)
        chain_hostnames(0);

# the time to wait before a died connection is re-established
        # (default is 60)
        time_reopen(10);

# the time to wait before an idle destination file is closed
        # (default is 60)
        time_reap(360);

# the number of lines buffered before written to file
        # you might want to increase this if your disk isn't catching with
        # all the log messages you get or if you want less disk activity
        # (say on a laptop)
        # (default is 0)
        sync(1);

# the number of lines fitting in the output queue
        log_fifo_size(16384);

# enable or disable directory creation for destination files
        create_dirs(yes);

# default owner, group, and permissions for log files
        # (defaults are 0, 0, 0600)
        #owner(root);
        group(adm);
        perm(0640);

# default owner, group, and permissions for created directories
        # (defaults are 0, 0, 0700)
        #dir_owner(root);
        #dir_group(root);
        dir_perm(0755);

# enable or disable DNS usage
        # syslog-ng blocks on DNS queries, so enabling DNS may lead to
        # a Denial of Service attack
        # (default is yes)
        use_dns(yes);
        dns_cache(yes);
        use_fqdn(yes);
        keep_hostname(yes);
        long_hostnames(off);

# maximum length of message in bytes
        # this is only limited by the program listening on the /dev/log Unix
        # socket, glibc can handle arbitrary length log messages, but -- for
        # example -- syslogd accepts only 1024 bytes
        # (default is 2048)
        #log_msg_size(2048);

#Disable statistic log messages.
    stats(43200);

# Some program send log messages through a private implementation.
    # and sometimes that implementation is bad. If this happen syslog-ng
    # may recognise the program name as hostname. Whit this option
    # we tell the syslog-ng that if a hostname match this regexp than that
    # is not a real hostname.
    bad_hostname("^gconfd$");
};

######
# sources

# all known message sources
source s_all {
        # message generated by Syslog-NG
        internal();
        # standard Linux log source (this is the default place for the syslog()
        # function to send logs to)
        unix-stream("/dev/log");
        # messages from the kernel
        file("/proc/kmsg" log_prefix("kernel: "));
        # use the following line if you want to receive remote UDP logging messages
        # (this is equivalent to the "-r" syslogd flag)
#        # udp();
};

######
# destinations

# some standard log files
destination df_auth { file("/var/log/auth.log"); };
destination df_syslog { file("/var/log/syslog"); };
destination df_cron { file("/var/log/cron.log"); };
destination df_daemon { file("/var/log/daemon.log"); };
destination df_kern { file("/var/log/kern.log"); };
destination df_lpr { file("/var/log/lpr.log"); };
destination df_mail { file("/var/log/mail.log"); };
destination df_user { file("/var/log/user.log"); };
destination df_uucp { file("/var/log/uucp.log"); };

# these files are meant for the mail system log files
# and provide re-usable destinations for {mail,cron,...}.info,
# {mail,cron,...}.notice, etc.
destination df_facility_dot_info { file("/var/log/$FACILITY.info"); };
destination df_facility_dot_notice { file("/var/log/$FACILITY.notice"); };
destination df_facility_dot_warn { file("/var/log/$FACILITY.warn"); };
destination df_facility_dot_err { file("/var/log/$FACILITY.err"); };
destination df_facility_dot_crit { file("/var/log/$FACILITY.crit"); };

# these files are meant for the news system, and are kept separated
# because they should be owned by "news" instead of "root"
destination df_news_dot_notice { file("/var/log/news/news.notice" owner("news")); };
destination df_news_dot_err { file("/var/log/news/news.err" owner("news")); };
destination df_news_dot_crit { file("/var/log/news/news.crit" owner("news")); };

# some more classical and useful files found in standard syslog configurations
destination df_debug { file("/var/log/debug"); };
destination df_messages { file("/var/log/messages"); };

# pipes
# a console to view log messages under X
destination dp_xconsole { pipe("/dev/xconsole"); };

# consoles
# this will send messages to everyone logged in
destination du_all { usertty("*"); };

######
# filters

# all messages from the auth and authpriv facilities
filter f_auth { facility(auth, authpriv); };

# all messages except from the auth and authpriv facilities
filter f_syslog { not facility(auth, authpriv); };

# respectively: messages from the cron, daemon, kern, lpr, mail, news, user,
# and uucp facilities
filter f_cron { facility(cron); };
filter f_daemon { facility(daemon); };
filter f_kern { facility(kern); };
filter f_lpr { facility(lpr); };
filter f_mail { facility(mail); };
filter f_news { facility(news); };
filter f_user { facility(user); };
filter f_uucp { facility(uucp); };

# some filters to select messages of priority greater or equal to info, warn,
# and err
# (equivalents of syslogd's *.info, *.warn, and *.err)
filter f_at_least_info { level(info..emerg); };
filter f_at_least_notice { level(notice..emerg); };
filter f_at_least_warn { level(warn..emerg); };
filter f_at_least_err { level(err..emerg); };
filter f_at_least_crit { level(crit..emerg); };

# all messages of priority debug not coming from the auth, authpriv, news, and
# mail facilities
filter f_debug { level(debug) and not facility(auth, authpriv, news, mail); };

# all messages of info, notice, or warn priority not coming form the auth,
# authpriv, cron, daemon, mail, and news facilities
filter f_messages {
        level(info,notice,warn)
            and not facility(auth,authpriv,cron,daemon,mail,news);
};

# messages with priority emerg
filter f_emerg { level(emerg); };

# complex filter for messages usually sent to the xconsole
filter f_xconsole {
    facility(daemon,mail)
        or level(debug,info,notice,warn)
        or (facility(news)
                and level(crit,err,notice));
};

######
# logs
# order matters if you use "flags(final);" to mark the end of processing in a
# "log" statement

# these rules provide the same behavior as the commented original syslogd rules

# auth,authpriv.*                 /var/log/auth.log
log {
        source(s_all);
        filter(f_auth);
        destination(df_auth);
};

# *.*;auth,authpriv.none          -/var/log/syslog
log {
        source(s_all);
        filter(f_syslog);
        destination(df_syslog);
};

# this is commented out in the default syslog.conf
# cron.*                         /var/log/cron.log
#log {
#        source(s_all);
#        filter(f_cron);
#        destination(df_cron);
#};

# daemon.*                        -/var/log/daemon.log
log {
        source(s_all);
        filter(f_daemon);
        destination(df_daemon);
};

# kern.*                          -/var/log/kern.log
log {
        source(s_all);
        filter(f_kern);
        destination(df_kern);
};

# lpr.*                           -/var/log/lpr.log
log {
        source(s_all);
        filter(f_lpr);
        destination(df_lpr);
};

# mail.*                          -/var/log/mail.log
log {
        source(s_all);
        filter(f_mail);
        destination(df_mail);
};

# user.*                          -/var/log/user.log
log {
        source(s_all);
        filter(f_user);
        destination(df_user);
};

# uucp.*                          /var/log/uucp.log
log {
        source(s_all);
        filter(f_uucp);
        destination(df_uucp);
};

# mail.info                       -/var/log/mail.info
log {
        source(s_all);
        filter(f_mail);
        filter(f_at_least_info);
        destination(df_facility_dot_info);
};

# mail.warn                       -/var/log/mail.warn
log {
        source(s_all);
        filter(f_mail);
        filter(f_at_least_warn);
        destination(df_facility_dot_warn);
};

# mail.err                        /var/log/mail.err
log {
        source(s_all);
        filter(f_mail);
        filter(f_at_least_err);
        destination(df_facility_dot_err);
};

# news.crit                       /var/log/news/news.crit
log {
        source(s_all);
        filter(f_news);
        filter(f_at_least_crit);
        destination(df_news_dot_crit);
};

# news.err                        /var/log/news/news.err
log {
        source(s_all);
        filter(f_news);
        filter(f_at_least_err);
        destination(df_news_dot_err);
};

# news.notice                     /var/log/news/news.notice
log {
        source(s_all);
        filter(f_news);
        filter(f_at_least_notice);
        destination(df_news_dot_notice);
};

# *.=debug;\
#         auth,authpriv.none;\
#         news.none;mail.none     -/var/log/debug
log {
        source(s_all);
        filter(f_debug);
        destination(df_debug);
};

# *.=info;*.=notice;*.=warn;\
#         auth,authpriv.none;\
#         cron,daemon.none;\
#         mail,news.none          -/var/log/messages
log {
        source(s_all);
        filter(f_messages);
        destination(df_messages);
};

# *.emerg                         *
log {
        source(s_all);
        filter(f_emerg);
        destination(du_all);
};

# daemon.*;mail.*;\
#         news.crit;news.err;news.notice;\
#         *.=debug;*.=info;\
#         *.=notice;*.=warn       |/dev/xconsole
log {
        source(s_all);
        filter(f_xconsole);
        destination(dp_xconsole);
};

#Extra entries for remote syslogging
source s_remote {
  udp();
};

destination df_host {
  file("/var/www/$HOST/$MONTH-$DAY.log"
  group("www-data")
  template("$YEAR-$MONTH-$DAY $PROGRAM $FACILITY $LEVEL $PRIORITY $MSG\n")  );
};

log {
  source(s_remote_all);
  destination(df_host);
};