112:
117:
An MTA works in the background, while the user usually interacts directly with a mail user agent. One may distinguish initial submission as first passing through an MSA—port 465 (or, for legacy reasons, optionally port 587) is used for communication between an MUA and an MSA, while port 25 is used
106:
trace header field to the top of the header of the message, thereby building a sequential record of MTAs handling the message. The process of choosing a target MTA for the next hop is also described in SMTP, but can usually be overridden by configuring the MTA software with specific routes.
73:
Messages exchanged across networks are passed between mail servers, including any attached data files (such as images, multimedia, or documents). These servers often keep mailboxes for email. Access to this email by end users is typically either by
102:(SMTP). When a recipient mailbox of a message is not hosted locally, the message is relayed, that is, forwarded to another MTA. Every time an MTA receives an email message, it adds a
183:
Submission of new email from a mail client is via SMTP, typically on port 587 or 465, and is now generally restricted to servers the user has an account with-such as their
133:(MDA). For this purpose the MTA transfers the message to the message handling service component of the message delivery agent (MDA). Upon final delivery, the
224:
MTA=Message
Transfer Agent (similar to X.400 name) is found, e.g., in RFC 1506, RFC 2476, RFC 3461, RFC 3464, RFC 3865, RFC 3888, RFC 6409, RFC 5598.
233:
MTA=Mail
Transfer Agent (similar to Mail Transfer Protocol) is found, e.g., in RFC 2298, RFC 2305, RFC 3804, RFC 3798, RFC 4496, RFC 5442, RFC 5429.
187:. This is for policy, not technical, reasons so that providers have some means of holding their users accountable for the generation of
330:
320:
170:
153:
for email - in which case they usually support some means for end users to access their email via a Mail User Agent (MUA), or
99:
55:
200:
291:
205:
130:
325:
91:
164:
129:
For recipients hosted locally, the final delivery of email to a recipient mailbox is the task of a
286:
149:
A relay or filtering server will typically store email only briefly, but other systems keep full
188:
119:
118:
for communication between MTAs, or from an MSA to an MTA. this distinction is clarified in
95:
314:
273:
154:
79:
138:
123:
54:
that transfers electronic mail messages from one computer to another using the
150:
17:
259:
for the format of an email message. Many MUAs allow users to see the raw
51:
75:
256:
111:
90:
A message transfer agent receives mail from either another MTA, a
31:
177:
184:
98:(MUA). The transmission details are specified by the
287:"What are the IPs that sends mail for a domain?"
263:directly, thereby allowing header inspection.
137:field is added to the envelope to record the
8:
58:. In some contexts, the alternative names
176:Proprietary systems, such as Microsoft's
217:
7:
27:Software to transfer electronic mail
25:
191:and other forms of email abuse.
171:Internet Message Access Protocol
110:
160:Common protocols for this are:
1:
100:Simple Mail Transfer Protocol
70:are used to describe an MTA.
56:Simple Mail Transfer Protocol
201:List of mail server software
347:
285:Bill Cole (29 June 2009).
244:Internet Mail Architecture
274:Email client#Port numbers
246:, D. Crocker (July 2009).
331:Message transfer agents
321:Internet mail protocols
206:Relay (disambiguation)
145:Transfer versus access
131:message delivery agent
36:message transfer agent
92:mail submission agent
257:Email#Message header
165:Post Office Protocol
30:Within the Internet
44:mail transfer agent
16:(Redirected from
338:
305:
304:
302:
300:
282:
276:
270:
264:
253:
247:
240:
234:
231:
225:
222:
136:
114:
105:
21:
346:
345:
341:
340:
339:
337:
336:
335:
311:
310:
309:
308:
298:
296:
284:
283:
279:
271:
267:
254:
250:
241:
237:
232:
228:
223:
219:
214:
197:
147:
134:
103:
96:mail user agent
88:
28:
23:
22:
15:
12:
11:
5:
344:
342:
334:
333:
328:
323:
313:
312:
307:
306:
277:
265:
261:message source
248:
235:
226:
216:
215:
213:
210:
209:
208:
203:
196:
193:
181:
180:
174:
168:
146:
143:
87:
84:
64:mail exchanger
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
343:
332:
329:
327:
324:
322:
319:
318:
316:
295:
293:
288:
281:
278:
275:
272:See table at
269:
266:
262:
258:
252:
249:
245:
239:
236:
230:
227:
221:
218:
211:
207:
204:
202:
199:
198:
194:
192:
190:
186:
179:
175:
172:
169:
166:
163:
162:
161:
158:
156:
152:
144:
142:
140:
132:
127:
125:
121:
115:
113:
108:
101:
97:
93:
85:
83:
81:
77:
71:
69:
65:
61:
57:
53:
49:
45:
41:
37:
33:
19:
326:Email agents
299:15 September
297:. Retrieved
294:mailing list
290:
280:
268:
260:
251:
243:
238:
229:
220:
182:
159:
155:email client
148:
128:
116:
109:
94:(MSA), or a
89:
80:email client
72:
67:
63:
59:
47:
43:
39:
35:
29:
18:Email server
139:return path
135:Return-Path
60:mail server
315:Categories
242:RFC 5598,
212:References
48:mail relay
34:system, a
151:mailboxes
86:Operation
195:See also
104:Received
52:software
76:webmail
68:MX host
173:(IMAP)
167:(POP3)
122:
78:or an
66:, or
46:, or
32:email
301:2009
292:ASRG
255:See
189:spam
178:MAPI
124:8314
185:ISP
120:RFC
50:is
42:),
40:MTA
317::
289:.
157:.
141:.
126:.
82:.
62:,
303:.
38:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
