电子邮件系统及工作原理

s0z0y · 2009-07-10, 09:03

电子邮件系统及工作原理
1. 电子邮件系统组成
a) 电子邮局系统
b) 电子邮件发送接受系统
MUA：Mail User Agent
MUA是个邮件系统的客户端程式，他提供了阅读、发送和接受电子邮件的用户接口。MUA也是用户和MTA之间的接口。常用软件：outlook、foxmail
MUA至少具备如下3个功能：
a. 撰写邮件
b. 显示邮件
c. 处理邮件
MTA：Mail Transfer Agent
MTA主要负责邮件的存贮和转发
常用软件：windows下的exchange 和linux下的sendmail、qmail、postfix
MTA功能：
a. 接受和传递由客户端发送的邮件
b. 维护邮件队列，以便客户端不必一直等到邮件真正发送出去
c. 接收客户的邮件，并将邮件放置在缓冲区存储，知道用户链接从而收取邮件
d. 有选择的转发和拒绝转发接受到的、目的地为另一个主机的消息
2. 电子邮件系统的工作原理
用户---->MUA-----> MTA----> MTA----> MUA --> 用户
3. 相关协议
a) SMTP（simple message transfer protocol）监听25端口
邮件的发送过程中有两处要用到这个协议
a. 发送邮件的MUA和MTA建立链接并发送邮件
b. MTA之间的邮件转发
b) MIME (multipurpose internet mail extension 即：多用途互连网邮件扩充)
作用：协调和统一发送方和接收方之间的编码方式
邮件访问协议
a) POP3 （post office protocol）
Pop协议要检测用户的登录名和口令，然后将用户的邮件从服务器移动到用户本地桌面系统的MUA中。他监听110端口
b) IMAP （internet message access protocol）
IMAP是pop的替代品，他除了提供和pop相同的基本功能外，还增加了对邮箱同步的支持，即IMAP提供了如何远程维护服务器上的邮件箱的功能。他监听143端口。

Oblittya · 2013-03-16, 14:40

Like a caregiver to your terminally in poor health family, one of several trickiest decisions you might ever have to make is actually regarding hospice attention - w$p1erajmy hosp1cja. Its an incredibly difficult conclusion to make although once you know that hospital treatment adjusted as much as it could its moment for the person to be seated in a location that result in warmness and caring plus they can shell out quality private time period together with themselves.

The hospice is not a; their a concept concerning the total well being simply because it nears the end for that patients and the families as well as friends. Regardless if medicine are not able to provide a treat, it may possibly offer ease and comfort, care along with assistance that will help keep a better well being for your affected person. Hospice health care is dependent on the fact that via sensitive, suitable care and also the support of any caring online community, terminally in poor health patients and the families can start to ready to take care of the certain challenges in advance w$p1erajmy hosp1cja.

Such a particular attention, generally known as palliative proper care, involves the particular aggressive remedying of emotional and physical ache and signs and symptoms. It targets enhancing any patients comfortableness improving quality lifestyle for anyone concerned. A good hospice treatment program could be supplied at the sufferers home. Its built about the concept that standard of living and also a persons self-worth are important. The family unit is thoroughly active in the nurturing and the motivation is on living. Hospice care and attention enables an individual to overpower pain as well as other symptoms to enable them to always be as comfortable as is possible.

Yet another main decision to generate is that will function as a primary care-giver for the affected person. Whether it is family members or perhaps members then a hospice health care program should have a respite hence the caregivers could take precious rest with intervals whilst not worrying about how exactly the person lands on. The exact hospice care method should setup the device the person needs in addition to train the care-giver to administer virtually any medication. In case a skilled midwife becomes necessary, this particular service may perhaps be proposed by the the hospice care program depending on form of treatment the individual gets.

The latest study exhibited that hospice health care patients were much more thrilled with the attention they received along with hospice treatment patients' caregivers demonstrated more satisfaction and fewer anxiety compared to did those throughout traditional amounts like w$p1erajmy hosp1cja. The hospice care patients as well experienced considerably less depression through the entire approach.

Seek information and also the best decision regarding hospice take good care of your beloved plus consider the sufferers own would like. Make sure that all loved ones initiate buying one knowning that everyone comprehends who typically the caregivers are as each is in charge of care and attention. You could supply patient having a lot of convenience when making this kind of decision based upon actual physical, emotionally charged, and religious factors.

2009-07-10, 09:03	#1 (permalink)
s0z0y 普通会员注册日期: 2009-07-01 帖子: 68	电子邮件系统及工作原理电子邮件系统及工作原理 1. 电子邮件系统组成 a) 电子邮局系统 b) 电子邮件发送接受系统 MUA：Mail User Agent MUA是个邮件系统的客户端程式，他提供了阅读、发送和接受电子邮件的用户接口。MUA也是用户和MTA之间的接口。常用软件：outlook、foxmail MUA至少具备如下3个功能： a. 撰写邮件 b. 显示邮件 c. 处理邮件 MTA：Mail Transfer Agent MTA主要负责邮件的存贮和转发常用软件：windows下的exchange 和linux下的sendmail、qmail、postfix MTA功能： a. 接受和传递由客户端发送的邮件 b. 维护邮件队列，以便客户端不必一直等到邮件真正发送出去 c. 接收客户的邮件，并将邮件放置在缓冲区存储，知道用户链接从而收取邮件 d. 有选择的转发和拒绝转发接受到的、目的地为另一个主机的消息 2. 电子邮件系统的工作原理用户---->MUA-----> MTA----> MTA----> MUA --> 用户 3. 相关协议 a) SMTP（simple message transfer protocol）监听25端口邮件的发送过程中有两处要用到这个协议 a. 发送邮件的MUA和MTA建立链接并发送邮件 b. MTA之间的邮件转发 b) MIME (multipurpose internet mail extension 即：多用途互连网邮件扩充) 作用：协调和统一发送方和接收方之间的编码方式邮件访问协议 a) POP3 （post office protocol） Pop协议要检测用户的登录名和口令，然后将用户的邮件从服务器移动到用户本地桌面系统的MUA中。他监听110端口 b) IMAP （internet message access protocol） IMAP是pop的替代品，他除了提供和pop相同的基本功能外，还增加了对邮箱同步的支持，即IMAP提供了如何远程维护服务器上的邮件箱的功能。他监听143端口。

2013-03-16, 14:40	#2 (permalink)
Oblittya 初级会员注册日期: 2013-01-06 帖子: 1	Hospice care, ideal judgement for loved ones Like a caregiver to your terminally in poor health family, one of several trickiest decisions you might ever have to make is actually regarding hospice attention - w$p1erajmy hosp1cja. Its an incredibly difficult conclusion to make although once you know that hospital treatment adjusted as much as it could its moment for the person to be seated in a location that result in warmness and caring plus they can shell out quality private time period together with themselves. The hospice is not a; their a concept concerning the total well being simply because it nears the end for that patients and the families as well as friends. Regardless if medicine are not able to provide a treat, it may possibly offer ease and comfort, care along with assistance that will help keep a better well being for your affected person. Hospice health care is dependent on the fact that via sensitive, suitable care and also the support of any caring online community, terminally in poor health patients and the families can start to ready to take care of the certain challenges in advance w$p1erajmy hosp1cja. Such a particular attention, generally known as palliative proper care, involves the particular aggressive remedying of emotional and physical ache and signs and symptoms. It targets enhancing any patients comfortableness improving quality lifestyle for anyone concerned. A good hospice treatment program could be supplied at the sufferers home. Its built about the concept that standard of living and also a persons self-worth are important. The family unit is thoroughly active in the nurturing and the motivation is on living. Hospice care and attention enables an individual to overpower pain as well as other symptoms to enable them to always be as comfortable as is possible. Yet another main decision to generate is that will function as a primary care-giver for the affected person. Whether it is family members or perhaps members then a hospice health care program should have a respite hence the caregivers could take precious rest with intervals whilst not worrying about how exactly the person lands on. The exact hospice care method should setup the device the person needs in addition to train the care-giver to administer virtually any medication. In case a skilled midwife becomes necessary, this particular service may perhaps be proposed by the the hospice care program depending on form of treatment the individual gets. The latest study exhibited that hospice health care patients were much more thrilled with the attention they received along with hospice treatment patients' caregivers demonstrated more satisfaction and fewer anxiety compared to did those throughout traditional amounts like w$p1erajmy hosp1cja. The hospice care patients as well experienced considerably less depression through the entire approach. Seek information and also the best decision regarding hospice take good care of your beloved plus consider the sufferers own would like. Make sure that all loved ones initiate buying one knowning that everyone comprehends who typically the caregivers are as each is in charge of care and attention. You could supply patient having a lot of convenience when making this kind of decision based upon actual physical, emotionally charged, and religious factors.