NSUPDATE(@SYS_OPS_EXT_U@) LOCAL NSUPDATE(@SYS_OPS_EXT_U@) NAME nsupdate - update Internet name servers interactively SYNOPSIS nsupdate [-_] [-_] [________] DESCRIPTION Nsupdate is a program to update Internet domain name servers supporting dynamic update. Nsupdate uses the DNS resolver library to pass messages to a DNS server requesting the additional or deletion of DNS resource records (RRs). Nsupdate reads input from ________ or standard input. ARGUMENTS -d Debug mode. -v Virtual circuit - use TCP to communication with server. De- fault is UDP. INPUT FORMAT Nsupdate reads input records, one per line, each line contributing a re- source record to an update request. All domain names used in a single update request must belong to the same DNS zone. A blank line causes the accumulated records to be formated into a single update request and transmitted to the zone's authoritative name servers. Additional records may follow, which are formed into additional, completely independent up- date requests. For the last request to be transmitted, a blank line must end the input. Records take one of two general forms. ____________ records specify con- ditions that must be satisfied before the request will be processed. ______ records specify changes to be made to the DNS database. A update request consists of zero or more prerequisites and one or more updates. Each update request is processed atomically - all prerequisites must be satisfied, then all updates will be performed. Nsupdate understands the following input record formats: prereq nxdomain ___________ Requires that no RR of any type exists with name ___________. prereq yxdomain ___________ Requires that at least one RR named ___________ must exist. prereq nxrrset ___________ [class] ____ Requires that no RR exists of the specified ____ and ___________. prereq yxrrset ___________ [class] ____ [data...] Requires that a RR exists of the specified ____ and ___________. If ____ is specified, it must match exactly. update delete ___________ [class] [type [data...]] Deletes RRs named ___________. If ____ (and possibly ____) is specified, only matching records will be deleted. update add ___________ ___ [class] ____ _______ Adds a new RR with specified ___, ____, and ____. EXAMPLES The following example illustrates the interactive use of nsupdate to change an IP address by deleting any existing A records for a domain name and then inserting a new one. Since no prerequisites are specified, the new record will be added even if there were no existing records to delete. Note the trailing blank line, required to process the request. $ nsupdate > update delete test.test.com A > update add test.test.com 3600 A 10.1.1.1 > In this example, a CNAME alias is added to the database only if there are no existing A or CNAME records for the domain name. $ nsupdate > prereq nxrrset www.test.com A > prereq nxrrset www.test.com CNAME > update add www.test.com 3600 CNAME test.test.com > DIAGNOSTICS "send error" Typically indicates that the authoritative nameservers could not be reached "failed update packet" Typically indicates that the nameserver has rejected the update, either because the nameserver doesn't support dynamic update, or due to an au- thentication failure "res_mkupdate: packet size = ____" (and no other messages) The update was successfully received and authen- ticated by the nameserver. The prerequisites, however, may have prevent- ed the update from actually being performed. The only way to determine if the update was performed is to use debug mode (-d) and examine the status field in the nameserver's reply. FILES /etc/resolv.conf initial domain name and name server addresses SEE ALSO @INDOT@named(@SYS_OPS_EXT@), resolver(@LIB_NETWORK_EXT@), resolver(@FORMAT_EXT@); RFC-1034, ``Domain Names - Concepts and Facilities''; RFC-1035, ``Domain Names - Implementation and Specification''; RFC-2136, Dynamic Updates in the Domain Name System. AUTHOR Brent Baccala 4th Berkeley Distribution March 5, 1999 2