import of dnsmasq-2.34.tar.gz

man/dnsmasq.8

@@ -219,6 +219,11 @@ server strictly in the order they appear in /etc/resolv.conf
 .B \-n, --no-poll
 Don't poll /etc/resolv.conf for changes.
 .TP
+.B --clear-on-reload
+Whenever /etc/resolv.conf is re-read, clear the DNS cache.
+This is useful when new nameservers may have different
+data than that held in cache.
+.TP
 .B \-D, --domain-needed
 Tells dnsmasq to never forward queries for plain names, without dots
 or domain parts, to upstream nameservers. If the name is not known
@@ -326,11 +331,11 @@ Disable negative caching. Negative caching allows dnsmasq to remember
 identical queries without forwarding them again. This flag disables
 negative caching.
 .TP
-.B \-0, --dns-forward-max
-Set the maximum number of concurrent DNS queries. Unanswered queries
-time out after 20 seconds. If you sometimes see the log message 
-"forwarding table overflow: check for server loops." then it is worth
-experimenting with this setting. The default value is 150.
+.B \-0, --dns-forward-max=<queries>
+Set the maximum number of concurrent DNS queries. The default value is
+150, which should be fine for most setups. The only known situation
+where this needs to be increased is when using web-server log file
+resolvers, which can generate large numbers of concurrent queries.
 .TP
 .B \-F, --dhcp-range=[[net:]network-id,]<start-addr>,<end-addr>[[,<netmask>],<broadcast>][,<default lease time>]
 Enable the DHCP server. Addresses will be given out from the range
@@ -363,7 +368,7 @@ addresses given via
 .B dhcp-host
 or from /etc/ethers will be served.
 .TP
-.B \-G, --dhcp-host=[[<hwaddr>]|[id:[<client_id>][*]]][net:<netid>][,<ipaddr>][,<hostname>][,<lease_time>][,ignore]
+.B \-G, --dhcp-host=[[<hwaddr>]|[id:[<client_id>][*]]][,net:<netid>][,<ipaddr>][,<hostname>][,<lease_time>][,ignore]
 Specify per host parameters for the DHCP server. This allows a machine
 with a particular hardware address to be always allocated the same
 hostname, IP address and lease time. A hostname specified like this
@@ -557,16 +562,21 @@ if known. "add" means a lease has been created, "del" means it has
 been destroyed, "old" is a notification of an existing lease when
 dnsmasq starts or a change to MAC address or hostname of an existing
 lease (also, lease length or expiry and client-id, if leasefile-ro is set).
-The process is run as any unprivileged user which dnsmasq
-runs as, so it may be necessary to inhibit dropping of the root user,
-using the
-.B -u
-directive, if the script needs root privs.
+The process is run as root (assuming that dnsmasq was originally run as
+root) even if dnsmasq is configured to change UID to an unprivileged user.
 The environment is inherited from the invoker of dnsmasq, and if the
-host provided a client-id, this is stored in the variable
-DNSMASQ_CLIENT_ID. If dnsmasq was compiled with HAVE_BROKEN_RTC, then
+host provided a client-id, this is stored in the environment variable
+DNSMASQ_CLIENT_ID. If the client provides vendor-class or user-class 
+information, these are provided in DNSMASQ_VENDOR_CLASS and 
+DNSMASQ_USER_CLASS0..DNSMASQ_USER_CLASSn variables, but only for the
+"add" actions, since these data are not held in dnsmasq's lease
+database. If dnsmasq was compiled with HAVE_BROKEN_RTC, then
 the length of the lease (in seconds) is stored in
-DNSMASQ_LEASE_LENGTH, otherwise the time of lease expiry is stored in DNSMASQ_LEASE_EXPIRES.
+DNSMASQ_LEASE_LENGTH, otherwise the time of lease expiry is stored in
+DNSMASQ_LEASE_EXPIRES. If a lease used to have a hostname, which is
+removed, an "old" event is generated with the new state of the lease, 
+ie no name, and the former name is provided in the environment 
+variable DNSMASQ_OLD_HOSTNAME.
 All file decriptors are
 closed except stdin, stdout and stderr which are open to /dev/null
 (except in debug mode).