Waarschuwingsinformatie op DHAP-hoogte instellen op ESA

Inleiding

Dit document beschrijft hoe u informatie kunt lokaliseren in verband met DHAP-waarschuwingen (Directory Harvest Prevention) op uw Cisco Email Security Appliance (ESA).

HEEP-incidenten lokaliseren vanuit de ESA

De ingangen die de gebeurtenis van DHAP beschrijven verblijven in de postlogs. Hier is een voorbeeld post logingang wanneer DHAP zich voordoet:

Tue Oct 18 00:25:35 2005 Warning: LDAP: Dropping connection due to potential Directory
 Harvest Attack from host=(192.168.10.1', None), dhap_limit=4, sender_group=SUSPECTLIST

Opmerking: standaard wordt 24/24 netmask in de zoekfunctie gezocht.

Voer deze zoekopdracht in in de CLI om de maillogs te bekijken:

myesa.local> grep "dhap_limit=" mail_logs

De DHCP-tellers omvatten zowel afwijzingen in de ontvangstentabel (RAT) als afwijzing van de Lichtgewicht Directory Access Protocol (LDAP)-acceptatie. De instellingen van DHAP worden gevormd in het beleid van de Stroom van de Post.

DHCP-configuratie bekijken of bijwerken vanuit de GUI

Voltooi deze stappen om de configuratieparameters van de DHCP-configuratie in de GUI te bekijken of te bewerken:

1. Navigeer naar Mail-beleid > Mail Flow.
   
   
2. Klik op de beleidsnaam om redits te maken of klik op Standaardbeleidsparameters om de huidige configuratie van DHCP te bekijken.
   
   
3. Breng indien nodig wijzigingen aan in het gedeelte Directory Harvest Prevention (DHAP):
   
   
   
   
4. Klik op Inzenden en vervolgens op Aanmelden om de wijzigingen op te slaan.

DHCP-configuratie bekijken of bijwerken vanuit CLI

Om uw de configuratieparameters van de DHAP van de CLI te bekijken of te bewerken, voer de listenerfig > bewerk [luisteraaraantal] > hostaccess > standaard opdracht in:

Default Policy Parameters
==========================
Maximum Message Size: 10M
Maximum Number Of Concurrent Connections From A Single IP: 10
Maximum Number Of Messages Per Connection: 10
Maximum Number Of Recipients Per Message: 50
Directory Harvest Attack Prevention: Enabled
Maximum Number Of Invalid Recipients Per Hour: 25
Maximum Number Of Recipients Per Hour: Disabled
Maximum Number of Recipients per Envelope Sender: Disabled
Use SenderBase for Flow Control: Yes 
Spam Detection Enabled: Yes
Virus Detection Enabled: Yes
Allow TLS Connections: No
Allow SMTP Authentication: No
Require TLS To Offer SMTP authentication: No
DKIM/DomainKeys Signing Enabled: No
DKIM Verification Enabled: No
SPF/SIDF Verification Enabled: No
DMARC Verification Enabled: No
Envelope Sender DNS Verification Enabled: No
Domain Exception Table Enabled: No
Accept untagged bounces: No

There are currently 5 policies defined.
There are currently 8 sender groups.

Choose the operation you want to perform:
- NEW - Create a new entry.
- EDIT - Modify an entry.
- DELETE - Remove an entry.
- MOVE - Move an entry.
- DEFAULT - Set the defaults.
- PRINT - Display the table.
- IMPORT - Import a table from a file.
- EXPORT - Export the table to a file.
- RESET - Remove senders and set policies to system default.
[]> default

Enter the default maximum message size. Add a trailing k for kilobytes, M for
 megabytes, or no letter for bytes. 
[10M]> 

Enter the maximum number of concurrent connections allowed from a single IP address. 
[10]> 

Enter the maximum number of messages per connection. 
[10]> 

Enter the maximum number of recipients per message. 
[50]> 

Do you want to override the hostname in the SMTP banner? [N]> 

Would you like to specify a custom SMTP acceptance response? [N]> 

Would you like to specify a custom SMTP rejection response? [N]> 

Do you want to enable rate limiting per host? [N]> 

Do you want to enable rate limiting per envelope sender? [N]> 

Do you want to enable Directory Harvest Attack Prevention per host? [Y]> 

Enter the maximum number of invalid recipients per hour from a remote host.
[25]> 

Select an action to apply when a recipient is rejected due to DHAP:
1. Drop
2. Code
[1]> 

Would you like to specify a custom SMTP DHAP response? [Y]> 

Enter the SMTP code to use in the response. 550 is the standard code.
[550]> 

Enter your custom SMTP response. Press Enter on a blank line to finish.

Would you like to use SenderBase for flow control by default? [Y]> 

Would you like to enable anti-spam scanning? [Y]> 

Would you like to enable anti-virus scanning? [Y]> 

Do you want to allow encrypted TLS connections?
1. No
2. Preferred
3. Required
4. Preferred - Verify
5. Required - Verify
[1]> 

Would you like to enable DKIM/DomainKeys signing? [N]> 

Would you like to enable DKIM verification? [N]> 

Would you like to change SPF/SIDF settings? [N]> 

Would you like to enable DMARC verification? [N]> 

Would you like to enable envelope sender verification? [N]> 

Would you like to enable use of the domain exception table? [N]> 

Do you wish to accept untagged bounces? [N]> 

Als u ervoor kiest om updates te maken, zorg er dan voor dat u terugkeert naar de belangrijkste CLI prompt en alle veranderingen toegewijd.

Gerelateerde informatie

• Cisco e-mail security applicatie - eindgebruikershandleidingen
• Technische ondersteuning en documentatie - Cisco-systemen