This is the command testmxlookup that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
testmxlookup - Look up mail relays for a domain
SYNOPSIS
testmxlookup [@ip-address] [--dnssec] [--udpsize n] {domain}
DESCRIPTION
testmxlookup lists the names and IP addresses of mail relays that receive mail for the
domain. This is useful in diagnosing mail delivery problems.
testmxlookup sends a DNS MX query for the specified domain, followed by A/AAAA queries, if
needed. testmxlookup lists the hostname and the IP address of every mail relay, and its
MX priority.
DIAGNOSTICS
The error message "Hard error" indicates that the domain does not exist, or does not have
any mail relays. The error message "Soft error" indicates a temporary error condition
(usually a network failure of some sorts, or the local DNS server is down).
OPTIONS
@ip-address
Specify the DNS server's IP address, where to send the DNS query to, overriding the
default DNS server addresses read from /etc/resolv.conf.
“ip-address” must be a literal, numeric, IP address.
--dnssec
Enable the DNSSEC extension. If the DNS server has DNSSEC enabled, and the specified
domain's DNS records are signed, the list of IP addresses is suffixed by “(DNSSEC)”,
indicating a signed response.
This is a diagnostic option. Older DNS servers may respond with an error, to a DNSSEC
query.
--udpsize n
Specify that n is the largest UDP packet size that the DNS server may send. This
option is only valid together with “--dnssec”. If “--dnssec” always returns an error,
try “--udpsize 512” (the default setting is 1280 bytes, which is adequate for
Ethernet, but other kinds of networks may impose lower limits).
Use testmxlookup online using onworks.net services
