I found some remote sites have set DNS balance, for example:
Code:
[root@MailServer ~]# dig -t MX 163.com
; <<>> DiG 9.2.4 <<>> -t MX 163.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9629
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;163.com. IN MX
;; ANSWER SECTION:
163.com. 17471 IN MX 50 mx.mail.163.com.
;; AUTHORITY SECTION:
163.com. 17475 IN NS ns.nease.net.
163.com. 17475 IN NS ns3.nease.net.
;; ADDITIONAL SECTION:
ns.nease.net. 172270 IN A 202.106.185.75
ns3.nease.net. 172270 IN A 220.181.28.3
;; Query time: 127 msec
;; SERVER: 202.96.209.6#53(202.96.209.6)
;; WHEN: Thu Dec 29 10:39:02 2005
;; MSG SIZE rcvd: 125
[root@MailServer ~]# dig mx.mail.163.com
; <<>> DiG 9.2.4 <<>> mx.mail.163.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64442
;; flags: qr rd ra; QUERY: 1, ANSWER: 9, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;mx.mail.163.com. IN A
;; ANSWER SECTION:
mx.mail.163.com. 191 IN CNAME mx.mail.163.split.netease.com.
mx.mail.163.split.netease.com. 493 IN A 220.181.12.53
mx.mail.163.split.netease.com. 493 IN A 220.181.12.54
mx.mail.163.split.netease.com. 493 IN A 220.181.12.55
mx.mail.163.split.netease.com. 493 IN A 220.181.12.56
mx.mail.163.split.netease.com. 493 IN A 220.181.12.57
mx.mail.163.split.netease.com. 493 IN A 220.181.12.58
mx.mail.163.split.netease.com. 493 IN A 220.181.12.51
mx.mail.163.split.netease.com. 493 IN A 220.181.12.52
;; AUTHORITY SECTION:
split.netease.com. 491 IN NS ns-split1.netease.com.
split.netease.com. 491 IN NS ns-split2.netease.com.
;; ADDITIONAL SECTION:
ns-split1.netease.com. 14908 IN A 202.106.168.79
ns-split2.netease.com. 14908 IN A 220.181.28.4
;; Query time: 86 msec
;; SERVER: 202.96.209.5#53(202.96.209.5)
;; WHEN: Thu Dec 29 10:39:25 2005
;; MSG SIZE rcvd: 281
I run dig for several times and get different orders indeed. But I found it's not true for postfix, for example:
Code:
Dec 29 10:41:19 MailServer postfix/qmgr[2775]: 28327F14267: to=<www.likiss00@163.com>, relay=none, delay=0, status=deferred (delivery temporarily suspended: connect to mx.mail.163.split.netease.com[220.181.12.56]: server refused to talk to me: 554 IP is rejected: 0,mx4,coCDDJlJs0Pu3pAL.60358S0 )
I found many such messages in maillog, and all the IP is "220.181.12.56" during a long time, maybe serveral hours, and I think the remote machines have been set to limit reciving mails number.
How does this occur and How to solve this problem?
Thanks.
