testmxlookup (1)
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Title: testmxlookup
Author: Sam Varshavchik
Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
Date: 07/24/2017
Manual: Double Precision, Inc.
Source: Courier Mail Server
Language: English
NAME
testmxlookup - Look up mail relays for a domainSYNOPSIS
- testmxlookup [@ip-address] [--dnssec] [--udpsize n] {domain}
DESCRIPTION
testmxlookup
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.
lqip-addressrq 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
lq(DNSSEC)rq, 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 lq--dnssecrq. If lq--dnssecrq always returns an error, try lq--udpsize 512rq (the default setting is 1280 bytes, which is adequate for Ethernet, but other kinds of networks may impose lower limits).
SEE ALSO
m[blue]courier(8)m[]
[1]
,
m[blue]RFC 1035m[][2]
.
AUTHOR
Sam Varshavchik
- Author
NOTES
- 1.
- courier(8)
- 2.
-
RFC 1035