MX-Relay FAQMarc Bakker2019-12-17T13:44:21+01:00

Here you will find answers to the most frequently asked questions (FAQs).

All technical questions

How to add a new domainMarc Bakker2019-12-10T16:13:42+01:00

Once you have an account you can easily add a domain. You do this via our portal. Go to “Dashboard” and click on the “Add Domain” icon:

Add Domain

First choose the product (inbound, outbound or both). Enter the new domain name, the IP address of the mail server and the number of mailboxes and you can (after adjusting the MX-Records) start immediately!

Can I use per user quarantine?Marc Bakker2019-12-10T16:15:35+01:00

That’s possible, you can give each user their own account and “in-box” on our filters. As soon as an e-mail arrive that meets the quarantine score, it will end up in the in-box and the user will receive a daily message with a nice overview and link to the web interface of our filters. Here you can view the messages and possibly release them.
Go as domain admin to “Basic”, “Spam Checking” and set the desired Quaratin score. This must be a score between your “Tag” and “Block” score.
Then go to “Basic”, “Quarantine” and make sure that the “Quarantine Type” is set to “Per-User”.
You are now ready and can use the Quarantine function.

Why would I use outbound filtering from MX-Relay?Marc Bakker2019-12-10T16:19:39+01:00

Most companies pay a lot of attention to filtering incoming e-mail, but forget the dangers of outgoing mail. E-mails are often sent directly to the destination and due to network weaknesses, such as unsecured wireless connections or firewalls that allow all kinds of devices to broadcast outbound SMTP, spam or malware can be sent through your network. With all its consequences! You will be placed on a blacklist, making it no longer possible to send e-mails. The administrators must look up the infected computers and remove the unwanted software. You are sometimes busy for days to get rid of the blacklist. In short, it takes a lot of time and money.

Can I deliver my outgoing mail to a different port?Marc Bakker2019-12-10T16:20:56+01:00

Yes this is possible! For many of our customers the standard port for e-mail (SMTP port 25) is blocked. As soon as you use our outgoing e-mail service you can already deliver to the following ports as standard:

25, 26, 27, 2525, 2500, 587

If you would like to deliver to another port, let us know by e-mail.

Quick search in the message overviewMarc Bakker2019-12-10T16:31:05+01:00

We have chosen on our systems to give the most capacity to handling e-mail messages, therefore the search through the messages is sometimes slow.

To make searching through all your messages faster, we have the following tips for you:

  • always set your browser language to “English”
  • always use a “time” filter before you begin your real search. Set this to eg all email from the last 3 days.



Where can I change the IP number of our mail server?Marc Bakker2019-12-10T16:39:53+01:00

You can easily change the IP address or FQDN under “Basic”, “IP Configuration”. At “Destination Server” you enter the IP address or FQDN of your mail server.

How do I delete a domain or stop the billing proces?Marc Bakker2019-12-10T16:41:17+01:00

After logging in to our portal, go to “Domains”. There you will see the option to delete the domain in addition to your domains.
Pay attention! As soon as you press “Delete”, the billing will stop, but the domain will also be immediately gone on our spam filters. So first make sure that the e-mail comes to your mail server via a different route.

Delete domain

I think I miss some messages in the message overview, why is that?Marc Bakker2019-12-16T14:16:24+01:00

Check the following setting under “Basic, Message Log”:

If the checkmark is marked at “Settings, Cluster Settings”, you will only see the results of one unit from a cluster.

A cluster consists of several units, a load balancer determines which message will be processed through which unit.

Can I get an account on the filter to view the configuration?Marc Bakker2019-12-16T14:17:54+01:00

That is possible, we can create users for you. This can be a user with only ‘view’ rights or a user who can also make changes to the configuration.

Tell us which user you want (must be an e-mail address within the domain) and we will create it for you. Just send us an e-mail.

My E-mail is on your blacklist, what can I do?Marc Bakker2019-12-10T16:37:33+01:00

Messages stopped with reason: “ZeroHour Intent” contains a part of a domain / URL that Barracuda sees malware coming from. If you have found the header information of the message, it looks like this:

Zerohour Intent



Putting the relevant domain “” on the whitelist makes no sense here. There can be viruses in the message and you don’t want them on your network. Y ou can go to the Barracuda website to see if the domain is currently on the intent list and to request a release. So under “lookup” type the part of the domain:

Barracuda lookups







In this example the domain is still on the Barracuda Intent list. In that case, contact for more information and a possible removal request.
Often it is not your own (or customer) domain, but the receiving third party that is on this list. So it is actually the responsibility of that party to get rid of this list. After all, all Barracuda users around the world will no longer receive email.

I occasionally still get spam in my mailbox, what can I do?Marc Bakker2019-12-10T16:38:44+01:00

If you still receive spam in your mailbox, you can do the following things:

Search for the relevant message in the message overview, check it and then go to “More Actions” and click on “Submit to Barracuda Central as Spam”.
If you cannot find the message in the message overview, there is a good chance that the email did not go through our filters, but was delivered directly to your mail server. Check whether the message has gone through our spam filters by looking in the header of the message to see if the message has been sent via one of our machines (filter01, cluster02 etc.). Sometimes a mail server on port 25 (SMTP) is still completely open and spammers can deliver mail directly to your mail server. The best thing to do is allow only smtp traffic from the spam cluster that contains your domains. Also don’t forget the access from our fallback server! See the overview of all our servers here.


How do I request outbound e-mail?Marc Bakker2019-12-10T16:46:20+01:00

Outbound e-mail can be requested in 2 ways, because you can already have a domain for inbound and decide to have it done outbound for that, or you come up with a completely new domain and you only want to do this outbound.

1) You already have a domain for inbound and also want outbound on it.
Log in to our portal, go to “Dashboard” and click on “Domains”. Your overview of domains will appear. Then click on “Request Outbound” here and the request will be placed.

2) You have a new domain, and you only want to do this outbound on it.
Go to the “Dashboard” in our portal again. Then click on “Add Domain”. Then first choose ‘Outbound’ and enter your domain etc. After this you will receive an e-mail from us confirming your request and you can start!

If we send e-mail via the outbound cluster, can I monitor here?Marc Bakker2019-12-10T16:46:56+01:00

No that is not possible. The outbound cluster is specially configured to send large amounts of messages. The spam score is a bit looser here, and white and / or blacklisting cannot be done. The main reason to send your e-mail via the dedicated outbound cluster is to minimize the chance of ending up on a blacklist and thereby upholding the reputation of your organization. Should something still go wrong during the sending, then in most cases the cluster will bounce the message to the mail server and you can see for yourself what exactly went wrong. If you nevertheless feel the need to exclude something, you can always send us an email with a request for a search.

Why does e-mail not arrive in the mailbox?Marc Bakker2019-12-10T16:49:08+01:00

This can have many different reasons. First do the following checks:

  • Check whether the MX records of the domain in question are correct. This is possible, for example, via the “MX Toolbox” website. If all goes well, then only MX records point to our spam filters. If there are also references to other machines, then it could be that some messages did not pass our filters via that MX record.
  • A second option is to look up the relevant message in our filter. Go to “Basic”, “Messagelog” and start your search. Once you have found the message, look at the following:
    • Action – Allowed, Whitelisted, Tagged, Quarantined, Blocked, Deferred, Encrypted, or Redirected.
    • Delivery Status – the status of the message in the outbound queue.
  • Double-click on the message and you will see slightly more information. The most important here are the “Action”, “Delivery Status” and “Delivery Detail”. If “Action” is Allowed, then the message is not blocked by our filter. In most cases, it says “Delivery Status” Rejected. In that case the mail server does not accept the message. Often you will see more information in the form of a short error code in the “Delivery Detail”.
Can I set up multiple servers?Marc Bakker2019-12-16T14:19:22+01:00

Yes, that’s possible. Go to the relevant domain on the filter and then To “Basic”, “IP Settings”. Here you can enter multiple IP numbers or Hostnames at the “Destination server”.

By separating the hostnames or IP numbers with a comma, the filter will begin to balance load. By putting a space between them, fail-over will be done.

Do you support DKIM?•Do you support DKIM?Marc Bakker2019-12-16T14:20:05+01:00

DKIM signs e-mails with a key, so that the recipient can check if the message has not been modified on the way. Our outbound service supports DKIM which means we send everything unchanged.

The signing must be done on the sending email server.

How do I use the fallback server?Marc Bakker2019-12-16T14:18:36+01:00

If our our main cluster is unavailable, you can use our fallback server for free. This is also just a spam filter, just like the main cluster. This cluster is at a completely different location and behind a different internet connection. However, you cannot log in on this yourself to adjust the configuration or to view the messages there as well. He is primarily there to receive the e-mail, should the main cluster be removed.

Requesting the fallback server goes through our portal website. After logging in, go to “Dashboard”, “Domains” and click on “Request” in the Fallback column at the relevant domain. After this you can enter the IP of the destination mail server and the domain will be created on the fallback server.

You will also receive an e-mail with information about how to adjust your MX record.

When do I opt for Outbound Service and when for SMTP service?Marc Bakker2019-12-16T14:20:45+01:00

If you want us to scan your outgoing e-mail traffic for 1 domain, choose the standard Outbound Service. If you have a mail server that runs multiple domains, choose our SMTP Service.

How long do you keep the e-mail?Marc Bakker2019-12-16T14:21:16+01:00

For troubleshooting we use a log rotation of 9 days. In the event that a client’s mail server has become unavailable, we will try to deliver these messages for up to 4 days. If you use the ‘per user quarantine’ function, we will keep those messages for a maximum of 30 days.

Which attachments do we block?Marc Bakker2019-12-16T14:22:12+01:00

We block the following attachments (these are also known in zip files):

– Executables – Windows Executables
– Executables – Windows Scripts
– *.pif
– *.scr

We put the following attachment types in quarantine (regardless of whether or not you use quarantine boxes):

– *.ade, *.adp, *.bas, *.bat, *.chm, *.cmd, *.com, *.cpl, *.crt, *.dll, *.hlp, *.hta, *.inf, *.ins, *.isp, *.js, *.jse, *.lnk, *.mdb, *.mde, *.msc, *.msi, *.msp, *.mst, *.pcd, *.reg, *.sct, *.shb, *.shs, *.vb, *.vbe, *.wsc, *.wsf, *.wsh

If you have a request to add certain attachment types, please send us an e-mail.

What is the maximum allowed size for an attachement?Marc Bakker2019-12-16T14:23:06+01:00

On the recommendation of the manufacturer we use a maximum size of 100MB. Do you often send larger files? Then we recommend using services such as

Can I still use your service if I use Office365 for my e-mail?Marc Bakker2019-12-16T14:24:34+01:00

Yes, that’s possible! It is even strongly recommended to also use our anti spam service. through our instruction manual you can finish the configuration within 20 minutes and you can start!

You can also read more about our protection against spam in office 365.


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