Ошибка почты host not found

Shorter answer.

With a “Host not found, try again.” it could mean that your server is having DNS resolution issues, or Postfix itself is having DNS resolution issues. But that is the core of what has to be cleaned up.

As for how to clear it up, your question doesn’t provide enough details on your base OS or setup to give a succinct answer. You seem to be running Ubuntu/Debian if you are running sudo service postfix restart, but what other details can you provide?

Longer answer.

Possibly connected to resolv.conf mysteriously disappearing.

Based on the error:

Host or domain name not found. Name service error for
name=smtp.gmail.com type=A: Host not found, try again.

It seems like you are using Gmail’s SMTP servers for outgoing mail. Unsure what your base OS is, but based on this answer on Ubuntu Forums this seems to be an issue with a missing resolv.conf on reboot; bold emphasis is mine:

I have the same problem on Ubuntu 14.04 LTS. When postfix is installed
it copies /etc/resolv.conf to /var/spool/postfix/etc/resolve.conf.
but for some reason after a reboot/restart the file is not copied and
you get the blank file with only the header.

The suggested temporary solution is to copy the main OS resolv.conf to Postfix’s directory:

sudo cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf

This isn’t a permanent fix it seems but at least it’s something to check out.

Possibly connected to inet_protocols settings.

Also this answer on Server Fault explains a similar situation which focuses on IPv6 support. Pretty sure your issue is not IPv6-related since the error is about a “type=A” record which is IPv4 and for IPv6 it would be “type=AAAA.” But that said, it might worth experimenting with adjusting the inet_protocols setting in your Postfix config file. Here is what the official Postfix documentation explains:

When IPv4 support is enabled via the inet_protocols parameter, Postfix
will look up DNS type A records, and will convert IPv4-in-IPv6 client
IP addresses (::ffff:1.2.3.4) to their original IPv4 form (1.2.3.4).
The latter is needed on hosts that pre-date IPV6_V6ONLY support (RFC
3493).

When IPv6 support is enabled via the inet_protocols parameter, Postfix
will do DNS type AAAA record lookups.

When both IPv4 and IPv6 support are enabled, the Postfix SMTP client
will choose the protocol as specified with the smtp_address_preference
parameter. Postfix versions before 2.8 attempt to connect via IPv6
before attempting to use IPv4.

Examples:

• inet_protocols = ipv4
• inet_protocols = all (DEFAULT)
• inet_protocols = ipv6
• inet_protocols = ipv4, ipv6

Assuming you are on an Ubuntu/Debian setup open up the config here:

sudo nano /etc/postfix/main.cf

And find—or set the value—to the inet_protocols line to be either this:

inet_protocols = ipv4

Or be this:

inet_protocols = all

Then restart the Postfix service—or the whole server—and see if that clears things up:

sudo service postfix restart

Shorter answer.

With a “Host not found, try again.” it could mean that your server is having DNS resolution issues, or Postfix itself is having DNS resolution issues. But that is the core of what has to be cleaned up.

As for how to clear it up, your question doesn’t provide enough details on your base OS or setup to give a succinct answer. You seem to be running Ubuntu/Debian if you are running sudo service postfix restart, but what other details can you provide?

Longer answer.

Possibly connected to resolv.conf mysteriously disappearing.

Based on the error:

Host or domain name not found. Name service error for
name=smtp.gmail.com type=A: Host not found, try again.

It seems like you are using Gmail’s SMTP servers for outgoing mail. Unsure what your base OS is, but based on this answer on Ubuntu Forums this seems to be an issue with a missing resolv.conf on reboot; bold emphasis is mine:

I have the same problem on Ubuntu 14.04 LTS. When postfix is installed
it copies /etc/resolv.conf to /var/spool/postfix/etc/resolve.conf.
but for some reason after a reboot/restart the file is not copied and
you get the blank file with only the header.

The suggested temporary solution is to copy the main OS resolv.conf to Postfix’s directory:

sudo cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf

This isn’t a permanent fix it seems but at least it’s something to check out.

Possibly connected to inet_protocols settings.

Also this answer on Server Fault explains a similar situation which focuses on IPv6 support. Pretty sure your issue is not IPv6-related since the error is about a “type=A” record which is IPv4 and for IPv6 it would be “type=AAAA.” But that said, it might worth experimenting with adjusting the inet_protocols setting in your Postfix config file. Here is what the official Postfix documentation explains:

When IPv4 support is enabled via the inet_protocols parameter, Postfix
will look up DNS type A records, and will convert IPv4-in-IPv6 client
IP addresses (::ffff:1.2.3.4) to their original IPv4 form (1.2.3.4).
The latter is needed on hosts that pre-date IPV6_V6ONLY support (RFC
3493).

When IPv6 support is enabled via the inet_protocols parameter, Postfix
will do DNS type AAAA record lookups.

When both IPv4 and IPv6 support are enabled, the Postfix SMTP client
will choose the protocol as specified with the smtp_address_preference
parameter. Postfix versions before 2.8 attempt to connect via IPv6
before attempting to use IPv4.

Examples:

• inet_protocols = ipv4
• inet_protocols = all (DEFAULT)
• inet_protocols = ipv6
• inet_protocols = ipv4, ipv6

Assuming you are on an Ubuntu/Debian setup open up the config here:

sudo nano /etc/postfix/main.cf

And find—or set the value—to the inet_protocols line to be either this:

inet_protocols = ipv4

Or be this:

inet_protocols = all

Then restart the Postfix service—or the whole server—and see if that clears things up:

sudo service postfix restart

Shorter answer.

With a “Host not found, try again.” it could mean that your server is having DNS resolution issues, or Postfix itself is having DNS resolution issues. But that is the core of what has to be cleaned up.

As for how to clear it up, your question doesn’t provide enough details on your base OS or setup to give a succinct answer. You seem to be running Ubuntu/Debian if you are running sudo service postfix restart, but what other details can you provide?

Longer answer.

Possibly connected to resolv.conf mysteriously disappearing.

Based on the error:

Host or domain name not found. Name service error for
name=smtp.gmail.com type=A: Host not found, try again.

It seems like you are using Gmail’s SMTP servers for outgoing mail. Unsure what your base OS is, but based on this answer on Ubuntu Forums this seems to be an issue with a missing resolv.conf on reboot; bold emphasis is mine:

I have the same problem on Ubuntu 14.04 LTS. When postfix is installed
it copies /etc/resolv.conf to /var/spool/postfix/etc/resolve.conf.
but for some reason after a reboot/restart the file is not copied and
you get the blank file with only the header.

The suggested temporary solution is to copy the main OS resolv.conf to Postfix’s directory:

sudo cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf

This isn’t a permanent fix it seems but at least it’s something to check out.

Possibly connected to inet_protocols settings.

Also this answer on Server Fault explains a similar situation which focuses on IPv6 support. Pretty sure your issue is not IPv6-related since the error is about a “type=A” record which is IPv4 and for IPv6 it would be “type=AAAA.” But that said, it might worth experimenting with adjusting the inet_protocols setting in your Postfix config file. Here is what the official Postfix documentation explains:

When IPv4 support is enabled via the inet_protocols parameter, Postfix
will look up DNS type A records, and will convert IPv4-in-IPv6 client
IP addresses (::ffff:1.2.3.4) to their original IPv4 form (1.2.3.4).
The latter is needed on hosts that pre-date IPV6_V6ONLY support (RFC
3493).

When IPv6 support is enabled via the inet_protocols parameter, Postfix
will do DNS type AAAA record lookups.

When both IPv4 and IPv6 support are enabled, the Postfix SMTP client
will choose the protocol as specified with the smtp_address_preference
parameter. Postfix versions before 2.8 attempt to connect via IPv6
before attempting to use IPv4.

Examples:

• inet_protocols = ipv4
• inet_protocols = all (DEFAULT)
• inet_protocols = ipv6
• inet_protocols = ipv4, ipv6

Assuming you are on an Ubuntu/Debian setup open up the config here:

sudo nano /etc/postfix/main.cf

And find—or set the value—to the inet_protocols line to be either this:

inet_protocols = ipv4

Or be this:

inet_protocols = all

Then restart the Postfix service—or the whole server—and see if that clears things up:

sudo service postfix restart

Короче ответ.

Если «Хост не найден, попробуйте еще раз». Это может означать, что на вашем сервере есть проблемы с разрешением DNS, или у самого Postfix есть проблемы с разрешением DNS. Но это суть того, что нужно очистить.

Что касается того, как это прояснить, ваш вопрос не содержит достаточно информации о вашей базовой ОС или настройке, чтобы дать краткий ответ. Похоже, вы работаете с Ubuntu/Debian, если вы запускаете sudo service postfix restart , но какую еще информацию вы можете предоставить?

Более длинный ответ.

Возможно, при подключении к resolv.conf загадочно исчезает.

На основании ошибки:

Имя хоста или домена не найдено. Ошибка службы имен для name = smtp.gmail.com type = A: Хост не найден, попробуйте еще раз.

Похоже, вы используете SMTP-серверы Gmail для исходящей почты. Не знаю, какая у вас базовая ОС, но, основываясь на этом ответе на форумах Ubuntu, похоже, это проблема с отсутствующим resolv.conf при перезагрузке; смелый акцент мой

У меня такая же проблема на Ubuntu 14.04 LTS. Когда postfix установлен, он копирует /etc/resolv.conf в /var/spool/postfix/etc/resolve.conf .
но по какой-то причине после перезагрузки / перезапуска файл не копируется и вы получаете пустой файл только с заголовком.

Предлагаемое временное решение — скопировать основную ОС resolv.conf в каталог Postfix:

sudo cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf

Кажется, это не постоянное исправление, но, по крайней мере, это то, что нужно проверить.

Возможно, связано с настройками inet_protocols .

Также этот ответ о сбое сервера объясняет аналогичную ситуацию, которая сосредоточена на поддержке IPv6. Уверен, что ваша проблема не связана с IPv6, поскольку ошибка связана с записью «type = A», которая является IPv4, а для IPv6 это будет «type = AAAA». Тем не менее, возможно, стоит поэкспериментировать с настройкой параметра inet_protocols в вашем конфигурационном файле Postfix. Вот что объясняет официальная документация Postfix:

Когда поддержка IPv4 включена через параметр inet_protocols, Postfix будет искать записи DNS типа A и преобразовывать IP-адреса клиентов IPv4-in-IPv6 (::ffff:1.2.3.4) в исходную форму IPv4 (1.2.3.4).
Последнее необходимо на хостах, которые поддерживают IPV6_V6ONLY (RFC 3493).

Когда поддержка IPv6 включена через параметр inet_protocols, Postfix будет выполнять поиск записей типа AAAA в DNS.

Если включена поддержка как IPv4, так и IPv6, SMTP-клиент Postfix выберет протокол в соответствии с параметром smtp_address_preference. Версии Postfix до 2.8 пытаются подключиться через IPv6, прежде чем использовать IPv4.

Примеры:

• inet_protocols = ipv4
• inet_protocols = all (ПО УМОЛЧАНИЮ)
• inet_protocols = ipv6
• inet_protocols = ipv4, ipv6

Предполагая, что вы находитесь на установке Ubuntu/Debian, откройте конфигурацию здесь:

sudo nano /etc/postfix/main.cf

И найдите или установите значение в строке inet_protocols чтобы оно было следующим:

inet_protocols = ipv4

Или будь таким:

inet_protocols = all

Затем перезапустите службу Postfix — или весь сервер — и посмотрите, не поможет ли это:

sudo service postfix restart

I’ve just installed Postfix on my Ubuntu, on a local network.

On this network, I have an Exchange Server (using domain mail.example.com).
I had a problem sending an email to a local address: adress@example.com:

relay=none, delay=0.01, delays=0.01/0/0/0, dsn=4.3.5, status=deferred 
(Host or domain name not found. Name service error for name=example.com
type=AAAA: Host found but no data record of requested type)

I solved this problem using relay_domain in my Postfix main.cf:

relay_domains = example.com
transport_maps = hash:/etc/postfix/transport

And in my /etc/postfix/transport:

example.com smtp:[mail.example.com]

Now I can send mails on @example.com, and I have tested some majors webmails (Gmail, Yahoo, Hotmail…). It works. But why I got this error on my adresses @example.com? How can I be sure I never find this error on another domain?

My Postfix configuration is:

postconf -n

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
inet_interfaces = all
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
mydestination = SRVWEB, localhost.localdomain, localhost
myhostname = SRVWEB
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relay_domains = domain.com
relayhost =
smtp_generic_maps = hash:/etc/postfix/generic
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
transport_maps = hash:/etc/postfix/transport

Добрый день. Возникла проблема с корпоративной почтой.

Есть домен, который был специально зарегистрирован для почты организации. Регистратор — r01.ru
Этот домен был успешно привязан на biz.mail.ru (т.е. в панели управления все MX, SPF, DKIM записи найдены и верны).

Сейчас наблюдается странная ситуация. Почта доходит, если письмо было отправлено с mail.ru или gmail.com, но НЕ доходит с Яндекс-ящиков.
При попытке отправить что-то на корпоративную почту с Яндекс ящика получается вот такое вот:

<105@2225555.ru>: Host or domain name not found. Name service error for
    name=2225555.ru type=AAAA: Host found but no data record of requested type

Статус доставки:

Reporting-MTA: dns; forward2m.mail.yandex.net
X-Yandex-Queue-ID: CC2505CA1BC8
X-Yandex-Sender: rfc822; linx@yandex.ru
Arrival-Date: Sat,  7 Feb 2015 10:51:44 +0300 (MSK)

Final-Recipient: rfc822; 105@2225555.ru
Original-Recipient: rfc822;105@2225555.ru
Action: failed
Status: 5.4.4
Diagnostic-Code: X-Yandex; Host or domain name not found. Name service error
    for name=2225555.ru type=AAAA: Host found but no data record of requested
    type

В чем может быть проблема в такой избирательности? Почему яндекс ни в какую не проходит?