Bounce outgoing messages immediately on DNS errors

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Bounce outgoing messages immediately on DNS errors

Ramprasad-5
We provide mail relay services to our clients , who send messages to us
via uucp and we send the messages out.

When someone mistypes a recipient domain name the mail gets stuck in our
queue with "host not found" errors and then gets bounces after 4 days
The client gets notified only after 4 days that his message was
rejected

I want to give a permanent failure to host-not-found DNS errors  at the
smtp level. I know this is possible at the incoming smtpd connection but
the problem is mails coming in via uucp are not thru smtpd


Thanks
Ram


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Re: Bounce outgoing messages immediately on DNS errors

Wietse Venema
ram:
> We provide mail relay services to our clients , who send messages to us
> via uucp and we send the messages out.
>
> When someone mistypes a recipient domain name the mail gets stuck in our
> queue with "host not found" errors and then gets bounces after 4 days
> The client gets notified only after 4 days that his message was
> rejected

Then you have a broken DNS server, or you have mis-configured
Postfix (soft_bounce, fallback_relay, etc.). Fix it.

        Wietse

> I want to give a permanent failure to host-not-found DNS errors  at the
> smtp level. I know this is possible at the incoming smtpd connection but
> the problem is mails coming in via uucp are not thru smtpd
>
>
> Thanks
> Ram
>
>
>
>

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Re: Bounce outgoing messages immediately on DNS errors

Ramprasad-5

On Mon, 2008-05-12 at 07:23 -0400, Wietse Venema wrote:

> ram:
> > We provide mail relay services to our clients , who send messages to us
> > via uucp and we send the messages out.
> >
> > When someone mistypes a recipient domain name the mail gets stuck in our
> > queue with "host not found" errors and then gets bounces after 4 days
> > The client gets notified only after 4 days that his message was
> > rejected
>
> Then you have a broken DNS server, or you have mis-configured
> Postfix (soft_bounce, fallback_relay, etc.). Fix it.
>

I think, I havent misconfigured my postfix server.
How do I confirm if DNS is broken

This is my postconf -n output
-------
alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
bounce_queue_lifetime = 1d
bounce_size_limit = 10000
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
default_destination_concurrency_limit = 40
default_process_limit = 100
delay_warning_time = 14h
header_checks = regexp:/etc/postfix/header_checks
hopcount_limit = 30
inet_interfaces = all
lmtp_generic_maps = hash:/etc/postfix/lmtp_maps
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_queue_lifetime = 5d
message_size_limit = 25480000
mime_header_checks = regexp:/etc/postfix/mime_header_checks
mydestination = $myhostname, localhost.$mydomain
mydomain = XXXXXXXXXXXX
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_rcpt_timeout = 100s
smtpd_banner = ESMTP
smtpd_client_connection_rate_limit = 20
smtpd_client_message_rate_limit = 20
smtpd_data_restrictions = reject_unauth_pipelining,
reject_multi_recipient_bounce,  permit
smtpd_recipient_limit = 50
smtpd_recipient_restrictions = check_recipient_access
hash:/etc/postfix/badrecipients   check_recipient_access
regexp:/etc/postfix/blockedrecipients   check_sender_access
hash:/etc/postfix/access   check_sender_access
hash:/etc/postfix/allowlist        check_client_access
cidr:/etc/postfix/allow_sender_ip,  permit_sasl_authenticated,
permit_mynetworks,      reject_unauth_destination
smtpd_restriction_classes = check_env_from
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain =
smtpd_sender_login_maps = hash:/etc/postfix/smtploginmaps
smtpd_sender_restrictions = check_client_access
cidr:/etc/postfix/permit_sender_ip,     check_sender_access
regexp:/etc/postfix/badsenders,    permit_mynetworks,
check_sender_access hash:/etc/postfix/sender_allow_domain,     permit
transport_maps = regexp:/etc/postfix/pop2_transport,
hash:/etc/postfix/ecm_transport
unknown_local_recipient_reject_code = 550

-------------


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Re: Bounce outgoing messages immediately on DNS errors

Wietse Venema
ram:

>
> On Mon, 2008-05-12 at 07:23 -0400, Wietse Venema wrote:
> > ram:
> > > We provide mail relay services to our clients , who send messages to us
> > > via uucp and we send the messages out.
> > >
> > > When someone mistypes a recipient domain name the mail gets stuck in our
> > > queue with "host not found" errors and then gets bounces after 4 days
> > > The client gets notified only after 4 days that his message was
> > > rejected
> >
> > Then you have a broken DNS server, or you have mis-configured
> > Postfix (soft_bounce, fallback_relay, etc.). Fix it.
>
> I think, I havent misconfigured my postfix server.
> How do I confirm if DNS is broken

The error message from the Postfix SMTP client will help to
distinguish between different causes.

What the result when you do

$ dig nxdomain.porcupine.org.

        Wietse

> This is my postconf -n output