The information in this page is updated in accordance with firmware version TRB2_R_00.02.06.1.
The DNS page is used to to set up how the device utilizes its own and other DNS servers.
This manual page provides an overview of the DNS windows in TRB245 devices.
If you're having trouble finding this page or some of the parameters described here on your device's WebUI, you should turn on "Advanced WebUI" mode. You can do that by clicking the "Basic" button under "Mode", which is located at the top-right corner of the WebUI.
General Settings[edit source]
The General Settings section is used to set up the main DNS parameters. Refer to the table below for information on each configuration field.
|Domain required||off | on; default: on||When enabled, stops forwarding queries for plain names, without dots or domain parts, to upstream nameservers. If the name is not known from /etc/hosts or DHCP then a "not found" answer is returned.|
|Local server||string; default: /lan/||Local domain specification. Names matching this domain are never forwarded and are resolved from DHCP or hosts files (/etc/hosts) only.|
|Local domain||domain name; default: lan||Local domain suffix appended to DHCP names and hosts file entries.|
|Log queries||off | on; default: off||When enabled, write received DNS requests to syslog.|
|DNS forwardings||string; default: none||List of DNS servers to forward requests to.|
|Rebind protection||off | on; default: on||Discards upstream RFC1918 responses. When enabled, the device will not resolve domain names for internal hosts.|
|Allow localhost||off | on; default: on||Allow upstream responses in the 127.0.0.0/8 range. For example, for RBL services.|
|Domain whitelist||domain name(s); default: none||List of domains to allow RFC1918 responses for.|
|Local Service Only||off | on; default: off||Limit DNS service to subnets and interfaces on which this device is serving as a DNS server.|
|Non-wildcard||off | on; default: on||Binds only to specific interfaces rather than wildcard address.|
|Listen Interfaces||network interface(s); default: none||Limits listening for DNS queries to interfaces specified in this field and loopback. Leave empty to listen on all interfaces.|
|Exclude Interfaces||network interface(s); default: none||Prevents listening for DNS queries on interfaces specified in this field. Leave empty to listen on all interfaces.|
Resolve and Hosts Files[edit source]
The Resolve and Hosts Files section is used to configure the usage of these files:
- /etc/hosts - the hosts file; contains hostname/IP address combinations for DNS hostname resolution; it is always checked first;
- /etc/resolv.conf - the resolve file; contains instructions that state the default search domain(s) that are used to complete a received query name into a fully qualified domain name (FQDN) when no domain suffix is provide.
Also contains a list of nameserver IP addresses for hostname resolution (DNS servers);
- /tmp/resolv.conf.auto - alternative resolve file, used for public hostname resolutions. The path to this file can be changed from this section.
Refer to the table below for information on each configuration field.
|Ignore resolve file||off | on; default: off||When enabled, doesn't read upstream servers from /etc/resolv.conf which is linked to the resolve file by default.|
|Resolve file||text file; default: none||Specifies an alternate DNS resolve file to use instead of the default one (/tmp/resolv.conf.auto).|
|Ignore /etc/hosts||off | on; default: off||Local domain suffix appended to DHCP names and hosts file entries.|
|Additional Hosts files||text file; default: none||Uploads a hosts files to use in addition to /etc/hosts.|
Advanced Settings[edit source]
The Advanced Settings section is used to set up some of the more specific DNS parameters. Refer to the table below for information on each configuration field.
|Filter private||off | on; default: on||Do not forward reverse lookups for local networks.|
|Filter useless||off | on; default: off||When disabled, does not forward requests that cannot be answered by public name servers.|
|Localise queries||off | on; default: on||Localise hostname depending on the requesting subnet if multiple IPs are available.|
|Expand hosts||off | on; default: on||Adds local domain suffix to names served from the hosts file(s).|
|No negative cache||off | on; default: off||When disabled, does not cache negative replies, i.e., "no such domain" responses.|
|Additional servers file||text file; default: none||Uploads an additional DNS servers file. This file may contain lines like 'server=/domain/22.214.171.124' or 'server=126.96.36.199' for domain-specific or full upstream DNS servers.|
|Strict order||off | on; default: off||When enabled, DNS servers will be queried in the order of the resolve file.|
|All Servers||off | on; default: off||When enabled, queries all available upstream DNS servers.|
|Bogus NX Domain Override||ip; default: none||List of hosts that supply bogus NX domain results.|
|DNS server port||integer [0..65535]; default: none||Listening port for inbound DNS queries.|
|DNS query port||integer [0..65535]; default: none||Fixed source port for outbound DNS queries.|
|Max. EDNS0 packet size||integer [0..9999999999999999]; default: none||Maximum allowed size of Extension Mechanisms for Domain Name System.0 UDP packets.|
|Max. concurrent queries||integer [0..9999999999999999]; default: none||Maximum allowed number of concurrent DNS queries.|
|Size of DNS query cache||integer [0..10000]; default: none||Number of cached DNS entries. Set to 0 for no caching.|