[Migrated from MSDN Exchange Dev]White list (domain or sender) - how to ByPass IPBlockListProvider

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White list (domain or sender) - how to ByPass IPBlockListProvider

[Original post]
Hi

I am running Exchange Server 2019 - Version 15.2
I would like some help regarding White list, I have configured white list in two location but RBL List from the IPBlockListProvider is always blocking FIRSTLY the IP.

How to bypass any check (antispam, rbl list) for a specific domain?
From example, I wanted to add hello@mybigspamtest.com to bypassed always by the AntiSpam.

1) From the ContentFilterConfig
I added here: Set-ContentFilterConfig -BypassedSenderDomains mybigspamtest.com t
result : if the IP is not from the RBL list (example SpamHaus), the antispam would not check this messager from mybigspamtest.com

But when the IP is blacklisted in the RBL List: this message is blocked and would not be received.

2) I test also to add this from the RULES with "ByPass spam filtering" but the Block List provider is always blocking first.

I am writing you also my configuration in my Transport agent policy is :

[PS] C:\Program Files\Microsoft\Exchange Server\V15\Scripts>Get-transportagent

So my question is how to bypass a domain or a specific sender correctly ?

many thanks

Answer 1

Hi,

Do you have an edge transport server configured with Connection filtering agent in your environment?
According to this article:

By default,the connection filter agent(which has the feature IPBlockListProvider)works first to filter the incoming mails.
So you need to configure it to bypass the specific domains.

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Answer 2

Thank you for your answer.

This Exchange sever 2019 is deployed in a standalone server. This is a single server with all the mailbox installed on this server. I do not find the Edge role installed with my check Get-ServerComponentState and Get-TransportAgent as I wrote in the first post.

I understand now better that the "Connection filter agent" is working before than the "Content filtering" but I could not find any settings how to bypass for a specific domain.

MailFlow/Rules is not working, this work only for content filtering Step.

The connection filter agent gives possibility to add and exclude an IP (Get-IPAllowListEntry) but not a domain or a specific mail address.

My question is how to exclude a specific domain or email from the connection filter Agent?

thank you

Answer 3

Hi, seems to work after setting this configuration bellow. I restart the Exchange service Transport but it take like 5 minutes before working.

Good test has been done with this anonymous email test https://emkei.cz/
There IP is blacklist from well known list like SpamHaus
So after adding for example the domain "mybigtest.com", this is working fine and I could receive emails from a blacklist server.

Last question, the microsoft documentation explain how to add the "white list domain":

Add-IPBlockListProvider -Name "Contoso IP Block List Provider" -LookupDomain rbl.contoso.com -BitmaskMatch 127.0.0.1

Is it important to add the

-BitmaskMatch 127.0.0.1

?

thank you.

My Setup:

[PS] C:\Program Files\Microsoft\Exchange Server\V15\Scripts>Get-IPAllowListProvidersConfig | Format-List *MailEnabled

ExternalMailEnabled : True
InternalMailEnabled : False

[PS] C:\Program Files\Microsoft\Exchange Server\V15\Scripts>Add-IPAllowListProvider -Name "mybigtest.com" -LookupDomain mybigtest.com

Name LookupDomain Priority

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mybigtest.com mybigtest.com 1

[PS] C:\Program Files\Microsoft\Exchange Server\V15\Scripts>Get-IPAllowListProvidersConfig | Format-List Enabled

Enabled : True

[PS] C:\Program Files\Microsoft\Exchange Server\V15\Scripts>Get-IPAllowListProvider

Name LookupDomain Priority

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mybigtest mybigtest.com 1

Answer 4

I have a new problem, after having adding the whitelist with the IPAllowListProvider:

• RBL List (block) is not working anymore: my current IPBlockListProvider (SpamHaus...Spamcom..etc..) is not working even if I restat also the server or the ms exchangetransport.

After removing the IPAllowListProvider with the commande line

Remove-IPAllowListProvider -identity

and restarted

Restart-Service MSExchangeTransport

IPBlockListProvider is working back.

So this is a problem because I cannot bypass any Sender or any domain from the connection filtering.

thank you for the help!

Answer 5

Any idea please?

I want to bypass an IP or a Domain in the connection filtering.

Currently, a server listed in RBL List from the IPBlockListProvider configured on exchange is not bypassed, I would like to know how can I do exception.

thank you