Domanda
Come è possibile evitare che l'ESA venga utilizzata come relè aperto?
Per evitare che l'ESA venga utilizzata come inoltro aperto, accertarsi di aver specificato i domini dei destinatari nella tabella di accesso ai destinatari (RAT) dei listener pubblici e che la voce "ALL" sia configurata su "Reject" (Rifiuta). Le voci RAT possono essere aggiunte tramite la GUI, nella scheda Mail Policies (Policy di posta). Di seguito è riportato un esempio che mostra come aggiungere un dominio, "example.com" alla RAT tramite la CLI.
mail.example.com> listenerconfig
Currently configured listeners:
1. InboundMail (on PublicNet, 172.19.1.80) SMTP TCP Port 25 Public
2. OutboundMail (on PrivateNet, 172.19.2.80) SMTP TCP Port 25 Private
Choose the operation you want to perform:
- NEW - Create a new listener.
- EDIT - Modify a listener.
- DELETE - Remove a listener.
- SETUP - Change global settings.
[]> edit
Enter the name or number of the listener you wish to edit.
[]> 1
Name: InboundMail
Type: Public
Interface: PublicNet (172.19.1.80/24) TCP Port 25
Protocol: SMTP
Default Domain:
Max Concurrency: 1000 (TCP Queue: 50)
Domain Map: Disabled
TLS: No
SMTP Authentication: Disabled
Bounce Profile: Default
Use SenderBase For Reputation Filters and IP Profiling: Yes
Footer: None
LDAP: Off
Choose the operation you want to perform:
- NAME - Change the name of the listener.
- INTERFACE - Change the interface.
- LIMITS - Change the injection limits.
- SETUP - Configure general options.
- HOSTACCESS - Modify the Host Access Table.
- RCPTACCESS - Modify the Recipient Access Table.
- BOUNCECONFIG - Choose the bounce profile to use for messages injected on
this listener.
- MASQUERADE - Configure the Domain Masquerading Table.
- DOMAINMAP - Configure domain mappings.
[]> rcptaccess
Recipient Access Table
There are currently 1 recipients.
Default Access: REJECT<
Choose the operation you want to perform:
- NEW - Create a new entry.
- EDIT - Modify an entry.
- IMPORT - Import a table from a file.
- EXPORT - Export the table to a file.
[]> new
Enter the recipient address for this entry.
Hostnames such as "example.com" and "[1.2.3.4]" are allowed.
Partial hostnames such as ".example.com" are allowed.
Usernames such as "postmaster@" are allowed.
Full email addresses such as "joe@example.com" or "joe@[1.2.3.4]" are allowed.
Separate multiple addresses with commas.
[]> example.com
Select the action to apply to this address:
1. Accept
2. Reject
[1]>
Would you like to specify a custom SMTP response? [N]>
Would you like to bypass receiving control for this entry? [N]>
Recipient Access Table
There are currently 2 recipients.
Default Access: REJECT
Choose the operation you want to perform:
- NEW - Create a new entry.
- EDIT - Modify an entry.
- DELETE - Remove an entry.
- PRINT - Display all entries.
- IMPORT - Import a table from a file.
- EXPORT - Export the table to a file.
- CLEAR - Remove all entries.
[]> print
ironport.com ACCEPT
ALL REJECT
Si noti che la voce "ALL" è configurata su "REJECT". In questo modo il sistema rifiuta i messaggi provenienti da qualsiasi host non configurato specificamente per essere accettato.
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