这是我dovecot.log的部分内容，我看不出有什么问题，麻烦请老师帮看看：
Sep 26 09:08:15 auth: Debug: auth client connected (pid=10097)
Sep 26 09:08:15 auth: Debug: client in: AUTH    1    PLAIN    service=imap    secured    lip=127.0.0.1    rip=127.0.0.1    lport=143    rport=41271    resp=d3VkaUB5eHN0dWR5Lm5ldAB3dWRpQHl4c3R1ZHkubmV0AHZpY2lvdXM=
Sep 26 09:08:15 auth-worker: Debug: sql(wudi@yxstudy.net,127.0.0.1): query: SELECT password FROM mailbox WHERE username='wudi@yxstudy.net' AND active='1'
Sep 26 09:08:15 auth: Debug: client out: OK    1    user=wudi@yxstudy.net
Sep 26 09:08:15 auth: Debug: master in: REQUEST    2375286785    10097    1    11e871789283ec56210eceaa524a10b8
Sep 26 09:08:15 auth-worker: Debug: sql(wudi@yxstudy.net,127.0.0.1): SELECT CONCAT(mailbox.storagebasedirectory, '/', mailbox.storagenode, '/', mailbox.maildir) AS home, CONCAT('*:bytes=', mailbox.quota*1048576) AS quota_rule FROM mailbox,domain WHERE mailbox.username='wudi@yxstudy.net' AND mailbox.domain='yxstudy.net' AND mailbox.enableimapsecured=1 AND mailbox.domain=domain.domain AND domain.backupmx=0 AND domain.active=1 AND mailbox.active=1
Sep 26 09:08:15 auth: Debug: master out: USER    2375286785    wudi@yxstudy.net    home=/var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14/    quota_rule=*:bytes=104857600
Sep 26 09:08:15 imap-login: Info: Login: user=<wudi@yxstudy.net>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, mpid=10098, secured
Sep 26 09:08:15 imap: Debug: Loading modules from directory: /usr/lib/dovecot
Sep 26 09:08:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib10_quota_plugin.so
Sep 26 09:08:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib11_imap_quota_plugin.so
Sep 26 09:08:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib20_autocreate_plugin.so
Sep 26 09:08:15 imap: Debug: Added userdb setting: plugin/quota_rule=*:bytes=104857600
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Effective uid=501, gid=501, home=/var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14/
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Quota root: name=user backend=dict args=:proxy::quotadict
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Quota rule: root=user mailbox=* bytes=104857600 messages=0
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=89128960 (85%) messages=0 reverse=no command=quota-warning 85 wudi@yxstudy.net
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=94371840 (90%) messages=0 reverse=no command=quota-warning 90 wudi@yxstudy.net
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=99614720 (95%) messages=0 reverse=no command=quota-warning 95 wudi@yxstudy.net
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: dict quota: user=wudi@yxstudy.net, uri=proxy::quotadict, noenforcing=0
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: maildir++: root=//var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir, index=, control=, inbox=//var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir, alt=
Sep 26 09:08:15 imap(wudi@yxstudy.net): Debug: Namespace : Using permissions from //var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir: mode=0700 gid=-1
Sep 26 09:08:15 imap(wudi@yxstudy.net): Info: Disconnected: Logged out bytes=233/876
Sep 26 09:09:15 auth: Debug: auth client connected (pid=10101)
Sep 26 09:09:15 auth: Debug: client in: AUTH    1    PLAIN    service=imap    secured    lip=127.0.0.1    rip=127.0.0.1    lport=143    rport=41276    resp=d3VkaUB5eHN0dWR5Lm5ldAB3dWRpQHl4c3R1ZHkubmV0AHZpY2lvdXM=
Sep 26 09:09:15 auth-worker: Debug: sql(wudi@yxstudy.net,127.0.0.1): query: SELECT password FROM mailbox WHERE username='wudi@yxstudy.net' AND active='1'
Sep 26 09:09:15 auth: Debug: client out: OK    1    user=wudi@yxstudy.net
Sep 26 09:09:15 auth: Debug: master in: REQUEST    3748134913    10101    1    6ddc1af1b1a7c30d9d793f5945c094b8
Sep 26 09:09:15 auth-worker: Debug: sql(wudi@yxstudy.net,127.0.0.1): SELECT CONCAT(mailbox.storagebasedirectory, '/', mailbox.storagenode, '/', mailbox.maildir) AS home, CONCAT('*:bytes=', mailbox.quota*1048576) AS quota_rule FROM mailbox,domain WHERE mailbox.username='wudi@yxstudy.net' AND mailbox.domain='yxstudy.net' AND mailbox.enableimapsecured=1 AND mailbox.domain=domain.domain AND domain.backupmx=0 AND domain.active=1 AND mailbox.active=1
Sep 26 09:09:15 auth: Debug: master out: USER    3748134913    wudi@yxstudy.net    home=/var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14/    quota_rule=*:bytes=104857600
Sep 26 09:09:15 imap-login: Info: Login: user=<wudi@yxstudy.net>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, mpid=10102, secured
Sep 26 09:09:15 imap: Debug: Loading modules from directory: /usr/lib/dovecot
Sep 26 09:09:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib10_quota_plugin.so
Sep 26 09:09:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib11_imap_quota_plugin.so
Sep 26 09:09:15 imap: Debug: Module loaded: /usr/lib/dovecot/lib20_autocreate_plugin.so
Sep 26 09:09:15 imap: Debug: Added userdb setting: plugin/quota_rule=*:bytes=104857600
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Effective uid=501, gid=501, home=/var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14/
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Quota root: name=user backend=dict args=:proxy::quotadict
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Quota rule: root=user mailbox=* bytes=104857600 messages=0
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=89128960 (85%) messages=0 reverse=no command=quota-warning 85 wudi@yxstudy.net
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=94371840 (90%) messages=0 reverse=no command=quota-warning 90 wudi@yxstudy.net
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Quota warning: bytes=99614720 (95%) messages=0 reverse=no command=quota-warning 95 wudi@yxstudy.net
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: dict quota: user=wudi@yxstudy.net, uri=proxy::quotadict, noenforcing=0
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: maildir++: root=//var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir, index=, control=, inbox=//var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir, alt=
Sep 26 09:09:15 imap(wudi@yxstudy.net): Debug: Namespace : Using permissions from //var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14//Maildir: mode=0700 gid=-1
Sep 26 09:09:15 imap(wudi@yxstudy.net): Info: Disconnected: Logged out bytes=233/876
Sep 26 09:10:01 auth: Debug: auth client connected (pid=10107)
Sep 26 09:10:04 auth: Debug: auth client connected (pid=10120)
Sep 26 09:10:04 auth: Debug: master in: USER    1    wudi@yxstudy.net    service=lda
Sep 26 09:10:04 auth-worker: Debug: sql(wudi@yxstudy.net): SELECT CONCAT(mailbox.storagebasedirectory, '/', mailbox.storagenode, '/', mailbox.maildir) AS home, CONCAT('*:bytes=', mailbox.quota*1048576) AS quota_rule FROM mailbox,domain WHERE mailbox.username='wudi@yxstudy.net' AND mailbox.domain='yxstudy.net' AND mailbox.enablelda=1 AND mailbox.domain=domain.domain AND domain.backupmx=0 AND domain.active=1 AND mailbox.active=1
Sep 26 09:10:04 auth: Debug: master out: USER    1    wudi@yxstudy.net    home=/var/vmail/vmail1/yxstudy.net/w/u/d/wudi-2012.09.20.19.00.14/    quota_rule=*:bytes=104857600
Sep 26 09:10:04 dict: Info: mysql(127.0.0.1): Connected to database vmail

系统退信内容如下：
This is the mail system at host yxstudy.net.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<example@exptest.net>: Command died with signal 6: "/usr/libexec/dovecot/deliver"

那要怎么在公网上做DNS解析呢？

没有，我在局域网测试的，只是改了etc/hosts文件，其他的没动

还是没有解决，麻烦关注一下，急～～～
谢谢！！

下载地址不好使

alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
biff = no
bounce_queue_lifetime = 1d
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
delay_warning_time = 0h
disable_vrfy_command = yes
enable_original_recipient = no
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = ipv4
mail_owner = postfix
mailbox_command = /usr/libexec/dovecot/deliver
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_backoff_time = 4000s
maximal_queue_lifetime = 1d
message_size_limit = 15728640
minimal_backoff_time = 300s
mydestination = $myhostname, localhost, localhost.localdomain, localhost.$myhostname
mydomain = sict.com
myhostname = mail.sict.com
mynetworks = 127.0.0.0/8
mynetworks_style = subnet
myorigin = mail.sict.com
newaliases_path = /usr/bin/newaliases.postfix
proxy_read_maps = $canonical_maps $lmtp_generic_maps $local_recipient_maps $mydestination $mynetworks $recipient_bcc_maps $recipient_canonical_maps $relay_domains $relay_recipient_maps $relocated_maps $sender_bcc_maps $sender_canonical_maps $smtp_generic_maps $smtpd_sender_login_maps $transport_maps $virtual_alias_domains $virtual_alias_maps $virtual_mailbox_domains $virtual_mailbox_maps $smtpd_sender_restrictions
queue_directory = /var/spool/postfix
queue_run_delay = 300s
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
recipient_bcc_maps = proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_domain.cf, proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_user.cf
recipient_delimiter = +
relay_domains = $mydestination, proxy:mysql:/etc/postfix/mysql/relay_domains.cf
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sender_bcc_maps = proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_domain.cf, proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_user.cf
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_data_init_timeout = 240s
smtp_data_xfer_timeout = 600s
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_end_of_data_restrictions = check_policy_service inet:127.0.0.1:10031
smtpd_enforce_tls = no
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks,permit_sasl_authenticated, check_helo_access pcre:/etc/postfix/helo_access.pcre
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, check_policy_service inet:127.0.0.1:7777, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_policy_service inet:127.0.0.1:10031
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain =
smtpd_sasl_path = ./dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = proxy:mysql:/etc/postfix/mysql/sender_login_maps.cf
smtpd_sender_restrictions = permit_mynetworks, reject_sender_login_mismatch, permit_sasl_authenticated
smtpd_tls_CAfile = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_cert_file = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_key_file = /etc/pki/tls/private/iRedMail.key
smtpd_tls_loglevel = 0
smtpd_tls_security_level = may
tls_random_source = dev:/dev/urandom
transport_maps = proxy:mysql:/etc/postfix/mysql/transport_maps_user.cf, proxy:mysql:/etc/postfix/mysql/transport_maps_domain.cf
unknown_local_recipient_reject_code = 550
virtual_alias_domains =
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql/virtual_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/catchall_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_catchall_maps.cf
virtual_gid_maps = static:501
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_maps.cf
virtual_minimum_uid = 501
virtual_transport = dovecot
virtual_uid_maps = static:501

谢谢，搞定了