Enhanced Mail System Status Codes
- Image by Ross Mayfield via Flickr
用低成本的办法建设一个稳健的,高效的邮件系统应该是每个系统管理员的梦想。现实中太多企业的 IT 人员喜欢采用商业的解决方案了。 在调试反垃圾系统的过程中,再次温习 dsn(delivery status notifications) 的含义。
Status codes thus consist of three numerical fields separated by ".". The first sub-field indicates whether the delivery attempt was successful (2= success, 4 = persistent temporary failure, 5 = permanent failure). The second sub-field indicates the probable source of any delivery anomalies, and the third sub-field denotes a precise error condition, if known. 对系统管理员,需要检查 dsn 不等于 2.0.0 的邮件,来保证邮件系统没有被滥用。例如: May 18 20:50:30 freelamp sendmail[6221]: n4ICmNJA006201: to=username@21cn.com, delay=00:01:59, xdelay=00:01:44, mailer=esmtp, pri= 181763, relay=mta.21cn.com. [59.36.102.53], dsn=4.0.0, stat=Deferred: Connection reset by mta.21cn.com. May 18 21:24:16 freelamp sendmail[10978]: n4ICmNJA006201: to=user@21cn.com, delay=00:35:45, xdelay=00:00:03, mailer=esmtp, pri =271763, relay=mta.21cn.com. [59.36.102.55], dsn=5.0.0, stat=Service unavailable
Related articles by Zemanta
- Logging Email From PHP Scripts (mneylon.com)
- Has my website been hacked into sending spam? (paceandkyeli.com)