I am trying to allow larger email sizes (20MB) and followed the advice given in the various threads here on the forum, including adjusting
Webmin -> Servers -> Postfix -> General Resource Control > "Max size of a message"
and also upped the file upload and http post PHP settings as suggested here
https://www.virtualmin.com/node/25404
even though I don't see how PHP is relevant for normal mail delivery.
I reloaded and restarted the postfix server, but still I get errors when trying to send a 16 MB image as an attachment.
/var/log/mail.log:
postfix/smtpd[27841]: NOQUEUE: reject: MAIL from mail-ig0-f182.google.com[209.85.213.182]: 552 5.3.4 Message size exceeds fixed limit; proto=ESMTP helo=<mail-ig0-f182.google.com>
The message size setting:
postconf | grep message_size_limit
message_size_limit = 20480000
The postfix configuration file
/etc/postfix/main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
virtual_alias_maps = hash:/etc/postfix/virtual
sender_bcc_maps = hash:/etc/postfix/bcc
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
home_mailbox = Maildir/
inet_interfaces = all
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
mydestination = $myhostname, localhost.$mydomain, localhost, <my FQDN>
mailbox_size_limit = 0
allow_percent_hack = no
smtpd_tls_cert_file = /etc/postfix/postfix.cert.pem
smtpd_tls_key_file = /etc/postfix/postfix.key.pem
smtpd_tls_CAfile = /etc/postfix/postfix.ca.pem
smtpd_tls_security_level = may
smtpd_tls_mandatory_protocols = SSLv3, TLSv1
smtpd_tls_mandatory_ciphers = high
alias_maps = hash:/etc/aliases, nis:mail.aliases
message_size_limit = 20480000
Howdy,
You may want to try setting your max message size just a little bit bigger than that... maybe 25 or 30MB.
When sending an attachment, it's first converted to text (MIME), which causes it to be a bit larger... 25% - 33% larger, if I remember correctly.
In your case, that would likely cause the message to be a bit larger than 20MB.
-Eric
Hi Eric, you're right. I wasn't aware of the MIME conversion causing an expansion. Thanks! Best regards, Ben