[CTX] [ALL]

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RESOLV parameter    ==  RESOLV=[resolver[,resolver]*]
          resolver  ==  resType[:[resParam][:[queryHostList][:clientHostList]]]
           resType  ==  cache | file | nis | dns | sys
                    --  default: RESOLV=cache,file,nis,dns,sys

Specify which name resolver should be used in what order.

cache	-- means cached result from following resolvers
file	-- means local hosts(5) file usually located at /etc/hosts,
nis	-- means hosts map on NIS or YP(4) service,
dns	-- means DNS service, and
sys	-- means using gethostbyname(2) and gethostbyaddr(2) which usually call system's standard resolver of the host.

If RESOLV is not specified, "sys" is disabled if the IP-address of the host of DeleGate is resolvable by "dns".
If empty value is specified as RESOLV="" then only hosts listed in HOSTS parameter can be resolved (this could be useful when you must hide hosts table for security consideration). Each resolver can be specified with optional argument like follows:

cache:/path	-- path name of cache directory [$TMPDIR/resolvy]
file:/path	-- path name of host-name file [/etc/hosts]
nis:nisDomain	-- NIS domain name [default domain]
dns:dnsHost	-- (a list of) DNS server

DNS Routing: A resolver can be applied to specific queries from specific clients. The optional queryHostList specifies for which hosts or addresses the resolver is applied. The optional clientHostList specifies for which client hosts the resolver is applied.

Example: selecting DNS servers depending on the inquired host/address

RESOLV="cache,dns:{192.168.1.2:8053}:{192.168.*,*.localdomain},dns:192.168.1.1"
// resolve local hosts with DNS sever at 192.168.1.2:8053
// and resolve others with 192.168.1.1:53
// this can be decomposed into a set of parameters like follows:
RESOLV="cache,dns:local-dns:local-hosts,dns:192.168.1.1"
HOSTLIST=local-dns:192.168.1.2:8053
HOSTLIST=local-hosts:192.168.*,*.localdomain


Example: selecting resolvers depending on the inquiring (client) DNS host

RESOLV="file:/etc/hosts:localHosts:192.168.*,dns:xx.xx.xx.xx"
HOSTLIST="localHosts:192.168.*,*.localdomain,*.mydomain"
// queries from local hosts (192.168.*) for "localHosts" are resolved
// with the file "/etc/hosts", others are resolved with the DNS server "xx.xx.xx.xx".

By default, a connection to a host which has multiple IP addresses is tried for each address in the order they are defined in each resolver. A special parameter HOSTS="*/*/RR" can be added to specify "Round Robin" where those IP addresses are tried in round robin order.

RES_WAIT parameter  ==  RES_WAIT=seconds:hostname
                    --  default: RES_WAIT="10:WWW.DeleGate.ORG"

Wait the resolver(s) to be ready before the DeleGate starts the initialization procedure. In the initialization, the result value of host-name resolution can be used as an important configuration parameter like ones for access control. The resolver of the host system may take time to be ready after the system's reboot, and could be unstable typically when the host address is assigned by DHCP. Therefore it might be not yet ready when the DeleGate started.
By default, DeleGate waits for 10 seconds until it can resolve a host name "WWW.DeleGate.ORG" by the given set of resolvers which is specified by the RESOLV parameter. You can specify a more appropriate host name or IP address to be used to detect the readiness of the resolvers. This feature can be disabled with RES_WAIT=0.

RES_CONF parameter  ==  RES_CONF=URL
                    --  default: RES_CONF="file:/etc/resolv.conf"
                        or from registry (on Windows)

Specify where the "resolv.conf" file is. The file is interpreted by the DeleGate original resolver named Resolvy. Resolvy recognizes "nameserver", "domain", "ndots", "search", and "sortlist" in it.

RES_NS parameter    ==  RES_NS=nsList
            nsList  ==  dnsServ[,nsList]
           dnsServ  ==  dnsServer[//socksV5Host] | END.
                    --  default: depend on RES_CONF

Specify a DNS server to be used: dnsServer is a host name or an IP-address of the host name DNS server, which may optionally be followed by port number, like "host:8053" when the port number is not standard port(53). With "dnsServer//socksV5Host", a DNS server beyond a firewall can be referred through the specified Socks V5 server. The Socks server is specified by its IP address with an optional port number like "192.168.1.1:2080".

By default, name servers listed in "resolv.conf" are added to the list of DNS servers to be used. A special dnsServ name ".END" disables to adding such name servers. For example, RES_NS="192.168.1.1,END." means using 192.168.1.1 only regardless of "resolv.conf".

RES_AF parameter    ==  RES_AF=afOrder
            afOrder ==  46 | 64 | 4 | 6
                    --  default: 46

Specify the ordered set of address families (IPv4 or IPv6) of the address of the host to be retrieved. The default value "46" means retrieving IPv4 address first, and if not found, then IPv6 address next.

RES_RR parameter    ==  RES_RR=HostList
                    --  default: RES_RR="*"

Round robin IP-address-list for the hosts included in the HostList. Currently, only RES_RR="*" and RES_RR="" are supported.

RES_VRFY parameter  ==  RES_VRFY=""
                    --  default: none

With "RES_VRFY=", results of reverse look-up of DNS server is verified. When an IPaddress1 is resolved to Hostname, and when the Hostname is resolved to IPaddress-list which does not include the IPaddress1, the verification fail and the result is ignored.

RES_DEBUG parameter ==  RES_DEBUG=number
                    --  default: none

The level of logging for debugging of the built-in resolver.

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