Frequently Asked Questions

Web Filter

Can I integrate the service with my Active Directory (AD) service?

Yes, CronLab’s Web Filter supports integration with LDAP and Kerberos, which can be used to integrate the filter with your AD service.

Do you scan for viruses?

In addition to filter for harmful URLs, an optional virus scanner is available on the service. This can even be switched on and off for speficic groups of users.

Do you have a local service for the web filter in the country where I am based?

CronLab have numerous Web Filtering servers scattered accross the world. Please contact your sales representative for your specific case.

How does the malware identification work in the URL lists?

Before any URL is put in the URL database they’re being put through several stages of URL analysis, content categorization and finally malicious website detection. In the malicious website detection there are several layers of control: static content scans, behavioural analysis, reputation analysis, exploit detection, sandboxes and more. Once a URL has been added to the database it is still checked by 100+ feeds that report if a URL needs to be updated. As soon as an update to the URL master database is done, this is immediately pushed out to all servers providing an instant protection and updated categorization.

In addition to this, CronLab also offers an optional anti-virus scanner to ensure a safe surfing experience.

Do you support roaming users?

Yes.

Can I create my own URL categories?

Yes.

Does the web filter support GMail Notifier?

Yes, in all cases as long as access to gmail.com is not being being blocked by the filter policies. If the softblock feature for gmail.com is switched on, the gmail.com page first needs to be unlocked through a web broswer as there is no support in the Gmail Notifier to unlock soft-blocked pages. Additionally, if the user is connecting from an IP set to “Let users surf without logging in from this IP” the user will need to register and login to the service, since the gmail notifier will not be able to use that feature of the filter.

Email Archiving

For how long do your archive my emails?

For as long as you want! This is up to the administrator to decide.

Can end users access the archived emails?

Yes, if allowed to do so by the administrator.

Can you help me import my historical emails from my PST-files / email server?

Yes, please contact your sales representative for details.

Anti-Spam

Does your service support all known email servers?

Yes, CronLab supports all known email servers, including Microsoft Exchange, Domino, MDeamon etc.

What is DKIM (DomainKeys Identified Mail) and how does it impact me?

DKIM or DomainKeys Identified Mail is a method to allow an organization to assume responsibility of a message. This in turn helps the recipient to validate the email as coming from a legitimate source. In our case CronLab assumes responsibility of all messages leaving its outgoing filtering servers by implementing DKIM with its own encryption keys. Therefore the IT administrator doesn’t need to make any adjustment to their settings but can rather be comforted by a higher deliverability rating thanks to CronLab implementing this technique.

More information available at: http://en.wikipedia.org/wiki/DKIM

What is SPF (Sender Policy Framework) and how should I set it up?

SPF or Sender Policy Framework is an email validation system, telling the receiving email server which the allowed senders for a certain domain are. Any user of CronLab’s outgoing filtering should include the string spf.cronlab.com in its DNS settings to ensure that CronLab’s servers are authorized to send information on behalf of their domains.

More information available at: http://en.wikipedia.org/wiki/Sender_Policy_Framework

Why should I reject unknown recepients and how do I do it?

There are two options in handling unknown recipients:

1) Block the email already at the transmission with a REJECT code
2) Accept the message, but subsequently returning it to the sender with a BOUNCE code

As virtually all senders of spam use forged from-addresses the BOUNCE code will result in an email to an innocent user, a so called backscatter. This could lead to the email server sending the BOUNCE to be blacklisted. It is therefore important to send a REJECT code already in the transmission to avoid any backscatter.

Additionally, CronLab counts its licenses based on number of users with a certain number of aliases allowed per user. Not implementing the REJECT code will quickly result in more email addresses being filtered than the license actually permits.

The following link explains how to set this up in Microsoft Exchange 2007:
http://technet.microsoft.com/en-us/library/bb123891%28EXCHG.80%29.aspx

Why do I get this error when sending mail: user_a@domain: Sender address rejected: not owned by user_b@domain?

To be able to send emails on behalf of someone else, you need to configure an alias. In the example above user_a@domain needs to login to his/her Message Center, and add user_b@domain as his/her alias.

The postmaster user may also configure a domain alias who will be granted permission to send emails on behalf of any user of the domain. See separate entry in the FAQ about this.

Port 25 is blocked for me. Can I use your service on other ports than port 25?

Yes.

I have a dynamic IP address. Can I use outgoing filtering through authentication?

Yes.

How can I change settings for the entire domain?

Log in as postmaster@domain in the Message Center. The postmaster account has higher level access privileges compared to regular users and can change settings on behalf of the entire domain.

Can I search through all emails, including spam?

The postmaster account at any domain can search through all messages for that domain, up to 30 days old. This only includes the header information (from-address, to-address, subject, etc) in order to preserve privacy. Any user can also search through his or her own spam and legitimate emails, unless this privilegie has been restricted by the postmaster.

My client says that he has sent me an email, but I have not received it. How can I check this?

In the search engine for the postmaster of every account you can trace all messages up to 5 days old, including detailed delivery information. If you cannot find the email at all in the search engine, then the email never even reached our filtering servers or that it was sent to an erroneous recipient.

How can I ensure that spammers don't send me emails directly without passing through your filtering servers?

The recommended approach is to change port number to a non-standard port.

Can I configure the Anti Spam service to use my redundant mail servers?

You need configure additional MX records in your DNS for your destination domain.

Example: if you are filtering example.com, and have your emailservers mail1.example.com and mail2.example.com, you should add the following entry to your DNS:

mail.example.com MX mail1.example.com, mail2.example.com

Thereafter, request CronLab to filter example.com and deliver to mail.example.com; then the filtering service will use mail1.example.com or mail2.example.com depending on priority and availability.

Finally, set your MX pointers for the domain to the ones given to you by CronLab.

Why does the filtering service say that there is a mail loop? I use redundant email servers.

This could be because there exists an errenous MX record for the destination domain, see above regarding redundant mail servers.

Is there a limitation to how large messages sent through your Anti-Spam solutions can be?

No. No such caps have been put in place.

We have recently added a new mailaddress but emails to this address are rejected by the spam filter?

The spam filter reloads all rejected email addressed within 3 hours. Please wait for 3 hours and the spam filter should allow for the emails to be sent through.

When trying to send emails through the outgoing filtering engine it says that they user isn’t authorized?

First of all, make sure you log in as the correct user when sending emails through the spam filter. If you are trying to send emails from a different user than the email address you are using to authenticate yourself, you have to set up a domain wide account for outgoing filtering. See separate entry in the FAQ about this

How do I set up an account for outgoing filtering that I can use for all users on my domain?

Log in to the partner portal as postmaster@domain. Go to the tab “Domain Configuration” and enter an email address under “Account used for domain wide outgoing filtering”. Generate a password for this email address on the Message Center by logging out from the message center and simply entering the email address at hand (without a password). Use this email address and the password generated to be able to send emails from any user at the domain.

Do you cache emails if our server goes down?

Yes, for 24h.

How often are quarantine messages sent out?

By default this is sent out on a daily basis to the users where something has changed in the quarantine. However you can set this as often or rarely as you want by logging in to the Message Center as postmaster and change this under Quarantine Configuration.

We want to use outgoing filtering for several domains, but can only configure one smarthost. How do we set this up?

First of all, all domains must be located on the same cluster (e.g. SWE01, SWE02, DEU01 etc). If they are, simply specify a domain account for outgoing filtering (see separate FAQ entry how to set this up) and set the master-domain as the smarthost.

Example: You use outgoing@domain_a.com as the domain account for domain_a.com and want to add outgoing filtering also for domain_b.com. Then logging in as postmaster for domain_b.com on the message center, set outgoing@domain_a.com as the outgoing filtering account under the tab “Domain Configuration”. Please don’t forget to wait the stated time before the new settings take place.

Spam Filtering, Web Filtering and Email Archiving