warning: no MX host for XYZ dot com has a valid address record

Periko Support

unread,

Aug 25, 2015, 2:28:47 PM8/25/15

to

Hi.
I receive a email from a user telling me that they have issues sending
emails to some company.

I have centos 5.11 x64 postfix 2:2.3.3-7.el5.

Now, I filter the domain and found this logs:

Aug 25 08:23:57 mail postfix/smtp[21291]: warning: no MX host for
XYZ.comhas a valid address record
Aug 25 08:46:08 mail postfix/smtp[22177]: warning: no MX host for
XYZ.com has a valid address record
Aug 25 09:19:18 mail postfix/smtp[23290]: warning: no MX host for
XYZ.com has a valid address record

I have more records.

Aug 25 10:18:23 mail postfix/smtp[28000]: warning: no MX host for
xyz.com has a valid address record
Aug 25 10:18:23 mail postfix/smtp[28000]: 21B5B1B0073:
to=<us...@xyz.com>, relay=none, delay=0.05, delays=0.05/0/0/0,
dsn=4.4.3, status=deferred (Host or domain name not found. Name
service error for name=inbound.registeredsite.com type=A: Host not
found, try again)
Aug 25 10:26:08 mail postfix/smtp[28578]: warning: no MX host for
xyz.com has a valid address record
Aug 25 10:26:08 mail postfix/smtp[28786]: warning: no MX host for
xyz.com has a valid address record
Aug 25 10:26:08 mail postfix/smtp[29046]: warning: no MX host for
xyz.com has a valid address record
Aug 25 10:26:08 mail postfix/smtp[28786]: 9AD001B0068:
to=<us...@xyz.com>, relay=none, delay=3582, delays=3572/0/10/0,
dsn=4.4.3, status=deferred (Host or domain name not found. Name
service error for name=inbound.registeredsite.com type=A: Host not
found, try again)
Aug 25 10:26:08 mail postfix/smtp[28578]: 8EBC41B006F:
to=<us...@xyz.com>, relay=none, delay=1767, delays=1757/0/10/0,
dsn=4.4.3, status=deferred (Host or domain name not found. Name
service error for name=inbound.registeredsite.com type=A: Host not
found, try again)
Aug 25 10:26:08 mail postfix/smtp[29046]: 36E361B0063:
to=<us...@xyz.com>, relay=none, delay=7341, delays=7331/0.01/10/0,
dsn=4.4.3, status=deferred (Host or domain name not found. Name
service error for name=inbound.registeredsite.com type=A: Host not
found, try again)

Just with that domain, some could help understand the issue? dns?

Thanks for your time!!!

Wolfe, Robert

unread,

Aug 25, 2015, 2:35:51 PM8/25/15

to

What this tells me is that the DNS entry for the domain the user is trying to send this to has no MX record, even though there is apparently a valid A record. However, someone on the list may correct me if I am incorrect.
________________________________________
From: owner-pos...@postfix.org [owner-pos...@postfix.org] on behalf of Periko Support [pheriko...@gmail.com]
Sent: Tuesday, August 25, 2015 1:28 PM
To: postfi...@postfix.org
Subject: warning: no MX host for XYZ dot com has a valid address record

I have more records.

Thanks for your time!!!

--
This message has been scanned for viruses and dangerous content by
E.F.A. Project, and is believed to be clean.

Click here to report this message as spam.
http://smtp.rivernet.us/cgi-bin/learn-msg.cgi?id=13EE1120AFF.A9BA4&token=713481a9ef4b2871ad4890afddadafb8

Viktor Dukhovni

unread,

Aug 25, 2015, 2:51:06 PM8/25/15

to

On Tue, Aug 25, 2015 at 11:28:27AM -0700, Periko Support wrote:

> Aug 25 08:23:57 mail postfix/smtp[21291]: warning: no MX host for

> XYZ.com has a valid address record
> Aug 25 08:46:08 mail postfix/smtp[22177]: warning: no MX host for
> XYZ.com has a valid address record
> Aug 25 09:19:18 mail postfix/smtp[23290]: warning: no MX host for
> XYZ.com has a valid address record

Is "xyz.com" the actual domain, or did you "anonymize" it?

$ dig +noall +ans +nocl +nottl -t mx xyz.com | sort -k3n
xyz.com. MX 1 aspmx.l.google.com.
xyz.com. MX 5 alt1.aspmx.l.google.com.
xyz.com. MX 5 alt2.aspmx.l.google.com.
xyz.com. MX 10 aspmx2.googlemail.com.
xyz.com. MX 10 aspmx3.googlemail.com.

But of course all those Gmail MX hosts do have IP addresses.

> Aug 25 10:26:08 mail postfix/smtp[29046]: 36E361B0063:
> to=<us...@xyz.com>, relay=none, delay=7341, delays=7331/0.01/10/0,
> dsn=4.4.3, status=deferred (Host or domain name not found. Name
> service error for name=inbound.registeredsite.com type=A: Host not
> found, try again)

However, your MX host with no IP address is not one of the above,
so you're wasting our time obfuscating the key piece of factual
data, namely the problem domain name.

Mind you, even that host also has an IP address:

$ dig +noall +ans +nocl +nottl -t a inbound.registeredsite.com
inbound.registeredsite.com. A 64.69.222.10

So it seems your DNS resolver is not terribly reliable, or that
domain was having some problems that are now resolved.

--
Viktor.

Wietse Venema

unread,

Aug 25, 2015, 2:52:57 PM8/25/15

to

Periko Support:

> Hi.
> I receive a email from a user telling me that they have issues sending
> emails to some company.
>
> I have centos 5.11 x64 postfix 2:2.3.3-7.el5.
>
> Now, I filter the domain and found this logs:
>

> Aug 25 08:23:57 mail postfix/smtp[21291]: warning: no MX host for

> XYZ.comhas a valid address record

> Aug 25 08:46:08 mail postfix/smtp[22177]: warning: no MX host for
> XYZ.com has a valid address record
> Aug 25 09:19:18 mail postfix/smtp[23290]: warning: no MX host for
> XYZ.com has a valid address record

DNS MX lookup succeeds, but the A lookup for the MX host(s) fails.
No further help is possible without concrete details.

Wietse

Periko Support

unread,

Aug 25, 2015, 3:03:07 PM8/25/15

to

Sorry, I anonymize the domain,which is: thxtransport dot com, thanks.

Viktor Dukhovni

unread,

Aug 25, 2015, 3:11:25 PM8/25/15

to

On Tue, Aug 25, 2015 at 12:02:53PM -0700, Periko Support wrote:

> Sorry, I anonymize the domain,which is: thxtransport dot com, thanks.

$ dig +noall +ans +nocl +nottl -t mx thxtransport.com
thxtransport.com. MX 5 inbound.registeredsite.com.

$ dig +noall +ans +nocl +nottl -t a inbound.registeredsite.com.
inbound.registeredsite.com. A 64.69.222.10

$ dig +noall +ans +nocl +nottl -t ns registeredsite.com. | sort
registeredsite.com. NS 1.ns.web.com.
registeredsite.com. NS 2.ns.web.com.
registeredsite.com. NS 3.ns.web.com.

$ dig +short -t ns registeredsite.com. | sort | while read ns; do dig +noall +nocl +nottl +ans -t a $ns; done
1.ns.web.com. A 64.69.208.141
2.ns.web.com. A 209.17.114.135
3.ns.web.com. A 64.69.208.143

If you're unable to resolve that address, debug your DNS resolver.

--
Viktor.

Periko Support

unread,

Aug 25, 2015, 3:49:16 PM8/25/15

to

Thanks for your help, looks like my dns was the issue, the third query
didn't return nothing, but the logs wasn't to clear.
The funny thing is that just with this domain show me the error.
I restart my dns and the query start working.
Thanks all for your help, I will check my dns, thanks.