Postfix / DNS issue, PLEASE HEP!

[uzla]

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:

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 :

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

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:

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!

[jledhead]

I can't remember if this is for chroot only, but check this file

/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.

[Lazydog]

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.