urlcp settings control DNS (hostname resolution):
dnsdomain(list) Takes a list of one or more search domains. Hostnames that do not contain a dot are searched for in each of these domains, in order. The default list is obtained from
/etc/resolv.confor the equivalent, depending on the system. Returns the previous list of domains. The limit is 5 domains. Has no effect if
sys. Added in version 3.01.960500000 20000608.
Sets the file to use for local hostname resolution, i.e. for the
hosts value of
dnsservices. The default is /etc/hosts on Unix, and %SYSTEMROOT%\System32\drivers\etc\hosts on Windows
(potentially altered by registry). Returns 0 on error.
Added in version 7.07.1550614572 20190219.
dnsigntc(boolean) Sets whether to ignore the TC (truncated message) flag in DNS replies. This flag may be set by the name server if the reply is too large to fit in one UDP packet and was truncated; a typical cause of this is a hostname with many IP addresses, e.g. DNS-based load management. Since only one IP is used from the reply, it is safe to ignore this flag. On by default. Added in version 3.01.982400000 20010216.
Sets the routines to use for domain name resolution. The second
argument is either
int to use the internal (non-blocking)
sys to use the system's C library
functions (blocking), or (in version 3.01.993260000 20010622 and
intsys which uses internal routines unless no
nameservers can be found in which case the system C library
functions are used. Returns the previous setting. The default is
intsys. (Version 3.01.993260000 20010622 and earlier
int and had no
intsys setting.) In
version 4.04.1068200000 20031106 and later, an empty string will
restore the default setting.
Note that the
intsys if no nameservers
found) routines are blocking: thus a
nslookup will in effect be serial, and slow DNS traffic
may even cause the timeout to be exceeded for some fetches. Also,
certain information and features of
nsinfo may be ignored if
sys mode is set, as well as
other DNS-related settings in
dnsrecurse(boolean) Sets whether to request recursion to other nameservers when resolving hostnames. The default is on. Added in version 3.01.989630000 20010511. Returns previous setting.
dnsretrans(integer) Sets the initial retransmit interval (in seconds) for DNS lookups. Has no effect if
sys. Default 5.
dnsretry(integer) Sets the max number of retries for DNS lookups. Returns previous setting. Has no effect if
sys. Default 4.
dnsservices(list) Takes a list of one or more of the strings
bind, indicating the name resolution services to use and the order in which to try them. Returns previous setting. Has no effect if
nameservers(list) Sets the list of nameservers to use, in order, for DNS resolution. Takes a list of dotted-decimal IP address strings, and returns the previous list of nameservers. Has no effect if
ipprotocols (here) has
no effect on what nameserver address(es) are permitted or
ipprotocols only affects the DNS query type
(A vs. AAAA) that is done (and the ultimate host
connection). Thus it is possible to use an IPv4-address
nameserver to query for and connect to an IPv6 host, and