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WDavid404 / Note_tryhackme

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SMTP #16

Open WDavid404 opened 9 months ago

WDavid404 commented 9 months ago

VRFY and EXPN.

VRFY request asks the server to verify an email address, EXPN asks the server for the membership of a mailing list.

e.g. Using nc to validate SMTP users

kali@kali:~$ nc -nv 192.168.50.8 25
(UNKNOWN) [192.168.50.8] 25 (smtp) open
220 mail ESMTP Postfix (Ubuntu)
VRFY root
252 2.0.0 root
VRFY idontexist
550 5.1.1 <idontexist>: Recipient address rejected: User unknown in local recipient table
^C

On windows client:

PS C:\Users\student> Test-NetConnection -Port 25 192.168.50.8

ComputerName     : 192.168.50.8
RemoteAddress    : 192.168.50.8
RemotePort       : 25
InterfaceAlias   : Ethernet0
SourceAddress    : 192.168.50.152
TcpTestSucceeded : True
WDavid404 commented 9 months ago

How SMTP work?

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