debian man page for testmxlookup

TESTMXLOOKUP(1) 					      Double Precision, Inc.						   TESTMXLOOKUP(1)

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).

SEE ALSO
       courier(8)[1], RFC 1035[2].

AUTHOR
       Sam Varshavchik
	   Author

NOTES
	1. courier(8)
	   [set $man.base.url.for.relative.links]/courier.html

	2. RFC 1035
	   http://www.rfc-editor.org/rfc/rfc1035.txt

Courier Mail Server						    11/18/2011							   TESTMXLOOKUP(1)