Recently I received spam report form my vps provider and Trend Micro, I think my vps got suspended because a or some unknow "blank sender" using my mail server as a "jump point", I know this is not a good description but it is almost like that.
So I google it, tried reject null sender config, smtpd_sender_restrictions and smtpd_reject_unlisted_sender, and non of these restrictions are working, the blank sender still using my mail server to probably sending spam email.
And I’m curious, why can’t I send emails with a blank sender username and password on my iPhone? He seems to be able to???
Here's the postfix log.
Aug 13 13:21:55 mail-srv postfix/qmgr[28609]: 80FE844028: from=<>, size=5295, nrcpt=1 (queue active)
Aug 13 13:21:55 mail-srv postfix/qmgr[28609]: 8AFCE6672B: from=<>, size=5519, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8EC7D4F0B9: from=<>, size=5909, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/error[29363]: 80914808C8: to=<[email protected]>, relay=none, delay=50028, delays=50028/0.01/0/0.02, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with smtp.huaku.com.tw[60.251.166.38] while performing the HELO handshake)
Aug 13 13:21:56 mail-srv postfix/error[29379]: 80FE844028: to=<[email protected]>, relay=none, delay=52167, delays=52167/0.01/0/0.01, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with smtp.huaku.com.tw[60.251.166.38] while performing the HELO handshake)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 893BC809E4: from=<>, size=5527, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8AB027F6F8: from=<>, size=5183, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/error[29367]: 8AFCE6672B: to=<[email protected]>, relay=none, delay=52306, delays=52306/0.02/0/0.01, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with smtp.huaku.com.tw[60.251.166.38] while performing the HELO handshake)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8C8A55B7C0: from=<>, size=5545, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/error[29360]: 8EC7D4F0B9: to=<[email protected]>, relay=none, delay=52263, delays=52263/0.02/0/0.01, dsn=4.4.2, status=deferred (delivery temporarily suspended: lost connection with smtp.huaku.com.tw[60.251.166.38] while performing the HELO handshake)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 864266EAD7: from=<>, size=5586, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8B1894C1FF: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8525D44E65: from=<>, size=5532, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89C656CE39: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 804E35CEC2: from=<>, size=5577, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8FF27451C4: from=<>, size=5516, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8730B5B32C: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8125063A9E: from=<>, size=5525, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 87BC557CD2: from=<>, size=5576, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8F3B957F44: from=<>, size=5526, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89D8D6EC93: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 86A845AA04: from=<>, size=5546, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8F5AB52661: from=<>, size=5543, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8C1CC5D9E5: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 80D597FBBF: from=<>, size=5557, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8146E57F4F: from=<>, size=5568, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8660B4F9D4: from=<>, size=5255, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89BD35A33C: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 87CC8599C5: from=<>, size=5610, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8E3A6584A0: from=<>, size=5116, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 847636A0B8: from=<>, size=5541, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 86AD480D58: from=<>, size=5542, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 817485AC90: from=<>, size=5556, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 841276EA0D: from=<>, size=5525, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8296F80B25: from=<>, size=5561, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8421063162: from=<>, size=5401, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8384E4B30E: from=<>, size=5161, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 82688821B0: from=<>, size=5566, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8CF625E8BB: from=<>, size=5368, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8EE4A518E1: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89AB64FF8B: from=<>, size=5226, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8AF1E5F0DA: from=<>, size=5674, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 877BA5EB02: from=<>, size=5547, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 866416EB06: from=<>, size=5551, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8B7FD6EE25: from=<>, size=5511, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8796465671: from=<>, size=5542, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89D9954689: from=<>, size=5536, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 883335CABD: from=<>, size=5539, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8FCBF67FAD: from=<>, size=5519, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8254B5DE8D: from=<>, size=5530, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8A27C5F0C2: from=<>, size=5398, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8522E50E32: from=<>, size=5428, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 84A5F80DD3: from=<>, size=5241, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 897F46EC86: from=<>, size=5545, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 89E504C571: from=<>, size=5929, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8A2946ECA8: from=<>, size=5566, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 88EC766A58: from=<>, size=5715, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8C51D4B594: from=<>, size=5577, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 812354E8B0: from=<>, size=5550, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 86C048267C: from=<>, size=5515, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8E3976CAFE: from=<>, size=5556, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 81A327FC62: from=<>, size=5572, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 85DDD660CB: from=<>, size=5550, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 847E150E1E: from=<>, size=5160, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8E5236F654: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8947E4E8EB: from=<>, size=5560, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8929F577DE: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 83A1B44F24: from=<>, size=5572, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8260D7FDB5: from=<>, size=5531, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8981C80C34: from=<>, size=5537, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 894AE808C9: from=<>, size=5566, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8CA3C4C831: from=<>, size=5490, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 866C548714: from=<>, size=5522, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 886658262D: from=<>, size=5556, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 822B95A9A8: from=<>, size=5525, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8BADC69D5E: from=<>, size=5525, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 852266B8C4: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 83712504BA: from=<>, size=5525, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8096D64F2C: from=<>, size=5311, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 842845DCEE: from=<>, size=5323, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8E3A159D01: from=<>, size=5545, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 85D255046D: from=<>, size=5540, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 806735809F: from=<>, size=5519, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8D4D56C900: from=<>, size=5539, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 869B057748: from=<>, size=5214, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8B9D682689: from=<>, size=5546, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 81D185E332: from=<>, size=5555, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 85D7C6318F: from=<>, size=5511, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 8F2915D8A7: from=<>, size=5565, nrcpt=1 (queue active)
Aug 13 13:21:56 mail-srv postfix/qmgr[28609]: 894F35C4A7: from=<>, size=5546, nrcpt=1 (queue active)
Aug 13 13:21:58 mail-srv postfix/local[29444]: fatal: main.cf configuration error: mailbox_size_limit is smaller than message_size_limit
Aug 13 13:21:59 mail-srv postfix/master[28607]: warning: process /usr/libexec/postfix/local pid 29444 exit status 1
Aug 13 13:21:59 mail-srv postfix/master[28607]: warning: /usr/libexec/postfix/local: bad command startup -- throttling
Aug 13 13:22:59 mail-srv postfix/local[29554]: fatal: main.cf configuration error: mailbox_size_limit is smaller than message_size_limit
Aug 13 13:23:00 mail-srv postfix/master[28607]: warning: process /usr/libexec/postfix/local pid 29554 exit status 1
Aug 13 13:23:00 mail-srv postfix/master[28607]: warning: /usr/libexec/postfix/local: bad command startup -- throttling
Aug 13 13:24:00 mail-srv postfix/local[29623]: fatal: main.cf configuration error: mailbox_size_limit is smaller than message_size_limit
Aug 13 13:24:01 mail-srv postfix/master[28607]: warning: process /usr/libexec/postfix/local pid 29623 exit status 1
Aug 13 13:24:01 mail-srv postfix/master[28607]: warning: /usr/libexec/postfix/local: bad command startup -- throttling
Aug 13 13:25:01 mail-srv postfix/local[29680]: fatal: main.cf configuration error: mailbox_size_limit is smaller than message_size_limit
Aug 13 13:25:02 mail-srv postfix/master[28607]: warning: process /usr/libexec/postfix/local pid 29680 exit status 1
Aug 13 13:25:02 mail-srv postfix/master[28607]: warning: /usr/libexec/postfix/local: bad command startup -- throttling
Here's postconf -n.
postconf: warning: /etc/postfix/master.cf: undefined parameter: submission_sender_checks
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
compatibility_level = 2
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
message_size_limit = 102400000
meta_directory = /etc/postfix
milter_default_action = accept
milter_protocol = 2
mydestination =
myhostname = mail-srv.novalocal
newaliases_path = /usr/bin/newaliases.postfix
non_smtpd_milters = inet:127.0.0.1:8891
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix3-3.4.7/README_FILES
sample_directory = /usr/share/doc/postfix3-3.4.7/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
shlib_directory = /usr/lib/postfix
smtp_tls_security_level = may
smtpd_milters = inet:127.0.0.1:8891
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, permit_auth_destination, reject_unauth_destination, reject_non_fqdn_sender, reject_unknown_sender_domain
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, permit_auth_destination, reject_unauth_destination, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_sender_login_mismatch
smtpd_tls_chain_files = /etc/pki/dovecot/private/dovecot.pem,/etc/pki/dovecot/certs/dovecot.pem
smtpd_tls_security_level = may
smtpd_use_tls = yes
tls_server_sni_maps = hash:/etc/postfix/vmail_ssl.map
unknown_local_recipient_reject_code = 550
virtual_alias_maps = sqlite:/etc/postfix/sqlite_virtual_alias_maps.cf, sqlite:/etc/postfix/sqlite_virtual_alias_domain_maps.cf, sqlite:/etc/postfix/sqlite_virtual_alias_domain_catchall_maps.cf
virtual_mailbox_domains = sqlite:/etc/postfix/sqlite_virtual_domains_maps.cf
virtual_mailbox_maps = sqlite:/etc/postfix/sqlite_virtual_mailbox_maps.cf, sqlite:/etc/postfix/sqlite_virtual_alias_domain_mailbox_maps.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp
word count exceeded.postconf -d here:https://paste.ubuntu.com/p/Nhqf7hbdg9/
