# man > HOST(1) > **TLDR:** Lookup Domain Name Server. > - Lookup A, AAAA, and MX records of a domain: `host {{domain}}` - Lookup a field (CNAME, TXT, ...) of a domain: `host -t {{field}} {{domain}}` - Reverse lookup an IP: `host {{ip_address}}` - Specify an alternate DNS server to query: `host {{domain}} {{8.8.8.8}}` *Source: tldr-pages* --- [_HOST_(1)](https://www.chedong.com/phpMan.php/man/HOST/1/markdown) BIND 9 [_HOST_(1)](https://www.chedong.com/phpMan.php/man/HOST/1/markdown) ## NAME host - DNS lookup utility ## SYNOPSIS **host **[**-aACdlnrsTUwv**] [**-c **class] [**-N **ndots] [**-p **port] [**-R **number] [**-t **type] [**-W **wait] [**-m** flag] [ [**-4**] | [**-6**] ] [**-v**] [**-V**] {name} [server] ## DESCRIPTION **host **is a simple utility for performing DNS lookups. It is normally used to convert names to IP addresses and vice versa. When no arguments or options are given, **host **prints a short sum‐ mary of its command-line arguments and options. **name **is the domain name that is to be looked up. It can also be a dotted-decimal IPv4 address or a colon-delimited IPv6 address, in which case **host **by default performs a reverse lookup for that address. **server **is an optional argument which is either the name or IP address of the name server that **host **should query instead of the server or servers listed in **/etc/re‐** **solv.conf**. ## OPTIONS ### -4 _-6_ option. ### -6 _-4_ option. ### -a ior of the _-l_ list zone option. ### -A records are omitted from the output. ### -c class This option specifies the query class, which can be used to lookup HS (Hesiod) or CH (Chaosnet) class resource records. The default class is IN (Internet). ### -C the SOA records for zone **name **from all the listed authoritative name servers for that zone. The list of name servers is defined by the NS records that are found for the zone. ### -d ### -l transfer of zone **name **and prints out the NS, PTR, and address records (A/AAAA). Together, the _-l_ _-a_ options print all records in the zone. ### -N ndots This option specifies the number of dots (**ndots**) that have to be in **name **for it to be considered absolute. The default value is that defined using the **ndots **statement in **/etc/resolv.conf**, or 1 if no **ndots **statement is present. Names with fewer dots are in‐ terpreted as relative names, and are searched for in the domains listed in the **search** or **domain **directive in **/etc/resolv.conf**. ### -p port This option specifies the port to query on the server. The default is 53. ### -r sion desired) bit in the query. This means that the name server receiving the query does not attempt to resolve **name**. The _-r_ option enables **host **to mimic the behavior of a name server by making non-recursive queries, and expecting to receive answers to those queries that can be referrals to other name servers. ### -R number This option specifies the number of retries for UDP queries. If **number **is negative or zero, the number of retries is silently set to 1. The default value is 1, or the value of the **attempts **option in **/etc/resolv.conf**, if set. ### -s sponds with a SERVFAIL response, which is the reverse of normal stub resolver behav‐ ior. ### -t type This option specifies the query type. The **type **argument can be any recognized query type: CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc. When no query type is specified, **host **automatically selects an appropriate query type. By default, it looks for A, AAAA, and MX records. If the _-C_ option is given, queries are made for SOA records. If **name **is a dotted-decimal IPv4 address or colon-delimited IPv6 address, **host **queries for PTR records. If a query type of IXFR is chosen, the starting serial number can be specified by ap‐ pending an equals sign (=), followed by the starting serial number, e.g., _-t_ _IXFR=12345678_. ### -T, -U _-T_ option makes it use a TCP connection when querying the name server. TCP is automat‐ ically selected for queries that require it, such as zone transfer (AXFR) requests. Type **ANY **queries default to TCP, but can be forced to use UDP initially via _-U_. ### -m flag This option sets memory usage debugging: the flag can be **record**, **usage**, or **trace**. The _-m_ option can be specified more than once to set multiple flags. ### -v output can also be enabled by setting the **debug **option in **/etc/resolv.conf**. ### -V ### -w also the _-W_ option. ### -W wait This options sets the length of the wait timeout, indicating that _named_ should wait for up to **wait **seconds for a reply. If **wait **is less than 1, the wait interval is set to 1 second. By default, **host **waits for 5 seconds for UDP responses and 10 seconds for TCP connec‐ tions. These defaults can be overridden by the **timeout **option in **/etc/resolv.conf**. See also the _-w_ option. ## IDN SUPPORT If **host **has been built with IDN (internationalized domain name) support, it can accept and display non-ASCII domain names. **host **appropriately converts character encoding of a domain name before sending a request to a DNS server or displaying a reply from the server. To turn off IDN support, define the **IDN_DISABLE **environment variable. IDN support is disabled if the variable is set when **host **runs. ## FILES ### /etc/resolv.conf ## SEE ALSO [_dig(1)](https://www.chedong.com/phpMan.php/man/dig/1/markdown)_, [_named(8)](https://www.chedong.com/phpMan.php/man/named/8/markdown)_. ## AUTHOR Internet Systems Consortium ## COPYRIGHT 2026, Internet Systems Consortium 9.18.39-0ubuntu0.24.04.5-Ubuntu 2025-08-13 [_HOST_(1)](https://www.chedong.com/phpMan.php/man/HOST/1/markdown)