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Guys, I'm stuffed. I had Postfix running on the server for months. But all over sudden it stopped sending emails to extarnal domains. I must fix it, but I run ...
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  1. #1
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    Aug 2008
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    Question Postfix / DNS issue, PLEASE HEP!


    Guys,

    I'm stuffed.

    I had Postfix running on the server for months. But all over sudden it stopped sending emails to extarnal domains. I must fix it, but I run out of ideas. PLEASE, HELP!

    Here is my sad story.

    Emails are Ok on the way from client app to my server. They are actually being stuck in the queue as deffered.

    So, I have checked logs:
    Code:
    Aug  6 22:01:50 www postfix/smtp[3592]: 4F0272264CF3: to=<uzla2010@googlemail.com>, 
    relay=none, delay=386320, delays=386264/0.06/56/0, dsn=4.4.3, status=deferred 
    (Host or domain name not found. Name service error for name=googlemail.com type=MX: Host not found, try again)
    "Host not found, try again" looks like it is a DNS issue.

    O'Reilly postfix definitive guide says: "The DNS query produced no answer. Either the DNS server is not reachable, or it is broken." It seems to be reasonable.

    So I have checked /etc/resolv.conf :
    Code:
    www:/etc# cat /etc/resolv.conf
    domain croup.de
    nameserver 208.84.145.233
    nameserver 208.84.145.155
    nameserver 208.77.96.36
    
    Then I checked  whether rimary DNS server is working:
    www:/etc# man nslookup
    Reformatting nslookup(1), please wait...
    www:/etc# nslookup
    > server 208.84.145.233
    Default server: 208.84.145.233
    Address: 208.84.145.233#53
    > set q=mx
    > googlemail.com
    Server:         208.84.145.233
    Address:        208.84.145.233#53
    
    Non-authoritative answer:
    googlemail.com  mail exchanger = 10 alt2.gmail-smtp-in.l.google.com.
    googlemail.com  mail exchanger = 50 gsmtp147.google.com.
    googlemail.com  mail exchanger = 50 gsmtp183.google.com.
    googlemail.com  mail exchanger = 5 gmail-smtp-in.l.google.com.
    googlemail.com  mail exchanger = 10 alt1.gmail-smtp-in.l.google.com.
    
    Authoritative answers can be found from:
    >
    and also

    Code:
    www:/etc# dig mx googlemail.com
    
    ; <<>> DiG 9.3.4 <<>> mx googlemail.com
    ;; global options:  printcmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39960
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 0
    
    ;; QUESTION SECTION:
    ;googlemail.com.                        IN      MX
    
    ;; ANSWER SECTION:
    googlemail.com.         598     IN      MX      50 gsmtp183.google.com.
    googlemail.com.         598     IN      MX      5 gmail-smtp-in.l.google.com.
    googlemail.com.         598     IN      MX      10 alt1.gmail-smtp-in.l.google.com.
    googlemail.com.         598     IN      MX      10 alt2.gmail-smtp-in.l.google.com.
    googlemail.com.         598     IN      MX      50 gsmtp147.google.com.
    
    ;; Query time: 1 msec
    ;; SERVER: 208.84.145.233#53(208.84.145.233)
    ;; WHEN: Wed Aug  6 22:08:01 2008
    ;; MSG SIZE  rcvd: 163
    
    www:/etc#
    SO, it seems that my server's DNS is working fine! (or not?)

    I even restarted postfix just in case.

    Now what do I have as a result:
    - postfix is up and running;
    - postfix accepting emails;
    - ostfix sends email to localdomains;
    - DNS seems to be working fine;
    - and IT DOES NOT SEND EMAILS TO EXTERANL DOMAINS!

    I'm really, really confused.

    Here is my config:
    Code:
    www:/home/uzla32# postconf -n
    alias_database = hash:/etc/aliases
    alias_maps = hash:/etc/aliases
    append_dot_mydomain = no
    biff = no
    broken_sasl_auth_clients = yes
    config_directory = /etc/postfix
    content_filter = amavis:[127.0.0.1]:10024
    inet_interfaces = all
    mailbox_size_limit = 0
    mydestination = www.myexamplesitename.com, localhost, localhost.localdomain
    myhostname = www.myexamplesitename.com
    mynetworks = 127.0.0.0/8
    myorigin = /etc/mailname
    proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $virtual_mailbox_limit_maps
    receive_override_options = no_address_mappings
    recipient_delimiter = +
    relayhost =
    smtp_tls_session_cache_database = btree:${queue_directory}/smtp_scache
    smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
    smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
    smtpd_sasl_auth_enable = yes
    smtpd_tls_cert_file = /etc/postfix/smtpd.cert
    smtpd_tls_key_file = /etc/postfix/smtpd.key
    smtpd_tls_session_cache_database = btree:${queue_directory}/smtpd_scache
    smtpd_use_tls = yes
    transport_maps = proxy:mysql:/etc/postfix/mysql-virtual_transports.cf
    virtual_alias_domains =
    virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf, mysql:/etc/postfix/mysql-virtual_email2email.cf
    virtual_gid_maps = static:5000
    virtual_mailbox_base = /home/vmail
    virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains.cf
    virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf
    virtual_uid_maps = static:5000

    Please, help!

    Many thanks in advance!

  2. #2
    Linux Engineer jledhead's Avatar
    Join Date
    Oct 2004
    Location
    North Carolina
    Posts
    1,077
    I can't remember if this is for chroot only, but check this file
    Code:
    /var/spool/postfix/etc/resolv.conf
    and make sure it matches /etc/resolv.conf

    I have never used postfix with amavis, but is amavis running on the server and the specified port. my understanding is that postfix queues mail, and sends it to amavis like another mail server, amavis filters it and sends it back. so if its not running that could cause problems but I don't know if it would have a different error.

  3. #3
    Linux Guru Lazydog's Avatar
    Join Date
    Jun 2004
    Location
    The Keystone State
    Posts
    2,677
    Check to see if your MX records are resolving. A lot of mail servers are not accepting mail from hosts they cannot verify. And they verify you with your MX records.

    Regards
    Robert

    Linux
    The adventure of a life time.

    Linux User #296285
    Get Counted

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