Hello

We have a server installed during the last year and we've not problems before yesterday. Suddenly all the messages to all different domains started to return 451 Error: Sorry, too many connections from "Internal IP". This occurs with destinations to gmail, hotmail, and other domains.

I've been trying several setups for bind but It seems not to be the problem. The complet log for a mail send to hotmail is:

Code:
Apr 12 20:19:36 mail amavis[13418]: (13418-01) FWD via SMTP: <admin@xxx.com> -> <yyy@hotmail.com>,BODY=7BIT 250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as A975B5029D0
Apr 12 20:19:36 mail amavis[13418]: (13418-01) Passed CLEAN, MYNETS LOCAL [192.1.1.151] [192.1.1.151] <admin@xxx.com> -> <yyy@hotmail.com>, Message-ID: <1674448408.5.1365790775139.JavaMail.root@xxx.com>, mail_id: FrgfPtEqvsEO, Hits: 3.679, size: 2152, queued_as: A975B5029D0, 563 ms
Apr 12 20:19:36 mail postfix/smtp[16275]: 1EB0B5028EB: to=<yyy@hotmail.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=0.6, delays=0.02/0.01/0.01/0.56, dsn=2.0.0, status=sent (250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as A975B5029D0)
Apr 12 20:19:36 mail postfix/qmgr[13669]: 1EB0B5028EB: removed
Apr 12 20:19:36 mail postfix/smtp[16279]: A975B5029D0: host mx3.hotmail.com[65.55.92.184] refused to talk to me: 451 Sorry, too many connections from 192.1.1.151, try again later
Apr 12 20:19:36 mail amavis[13418]: (13418-01) extra modules loaded: /opt/zimbra/zimbramon/lib/x86_64-linux-gnu-thread-multi/auto/Net/SSLeay/autosplit.ix, /opt/zimbra/zimbramon/lib/x86_64-linux-gnu-thread-multi/auto/Net/SSLeay/randomize.al, IO/Socket/SSL.pm, Net/LDAP/Extension.pm, Net/SSLeay.pm
Apr 12 20:19:36 mail postfix/smtp[16279]: A975B5029D0: host mx1.hotmail.com[65.54.188.110] refused to talk to me: 451 Sorry, too many connections from 192.1.1.151, try again later
Apr 12 20:19:36 mail postfix/smtp[16279]: A975B5029D0: host mx3.hotmail.com[65.55.37.120] refused to talk to me: 451 Sorry, too many connections from 192.1.1.151, try again later
Apr 12 20:19:36 mail postfix/smtp[16279]: A975B5029D0: host mx4.hotmail.com[65.55.37.104] refused to talk to me: 451 Sorry, too many connections from 192.1.1.151, try again later
Apr 12 20:19:36 mail postfix/smtp[16279]: A975B5029D0: to=<yyy@hotmail.com>, relay=mx2.hotmail.com[65.55.92.168]:25, delay=0.04, delays=0.01/0.01/0.02/0, dsn=4.0.0, status=deferred (host mx2.hotmail.com[65.55.92.168] refused to talk to me: 451 Sorry, too many connections from 192.1.1.151, try again later)
Dig returns:

any:

Code:
; <<>> DiG 9.7.0-P1 <<>> domain.com any
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10960
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 1

;; QUESTION SECTION:
;domain.com.                 IN      ANY

;; ANSWER SECTION:
domain.com.          604800  IN      SOA     domain.com. root.domain.com. 2 604800 86400 2419200 604800
domain.com.          604800  IN      MX      10 mail.domain.com.
domain.com.          604800  IN      NS      mail.domain.com.
domain.com.          604800  IN      A       192.1.1.151

;; ADDITIONAL SECTION:
mail.domain.com.     604800  IN      A       192.1.1.151

;; Query time: 0 msec
;; SERVER: 192.1.1.151#53(192.1.1.151)
;; WHEN: Fri Apr 12 20:21:49 2013
;; MSG SIZE  rcvd: 155
mx:

Code:
; <<>> DiG 9.7.0-P1 <<>> domain.com mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42938
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1

;; QUESTION SECTION:
;domain.com.                 IN      MX

;; ANSWER SECTION:
domain.com.          604800  IN      MX      10 mail.domain.com.

;; AUTHORITY SECTION:
domain.com.          604800  IN      NS      mail.domain.com.

;; ADDITIONAL SECTION:
mail.domain.com.     604800  IN      A       192.1.1.151

;; Query time: 0 msec
;; SERVER: 192.1.1.151#53(192.1.1.151)
;; WHEN: Fri Apr 12 20:23:57 2013
;; MSG SIZE  rcvd: 82
host $(hostname)
Code:
mail.domain.com has address 192.1.1.151
I've been searching this errors 451 relative to Zimbra and Postfix but I cannot find the solution. Also I cannot understand why an internet server like hotmail (or another else) returns the missatge with internal IP: 451 Sorry, too many connections from 192.1.1.151

Thanks in advance