This page is here to answer questions as we grow or knowledge base we will add to this page and add links under it.
To start here are some questions that you might need to know about DK Systems email services.
This is probably the most difficult task as an email administrator and near impossible to stop all Spam we have several techniques in place to reduce Spam. Spammers are constantly changing their tactics. We have several layers of protection we use to eliminate as much Spam as we can. First, at our firewall we block known Spamming IP addresses. The next layer all incoming and outgoing emails go though our Master Spam filter server. Our Master Spam filter server uses SpamAssassin and so emails go through a series of rules. If it fails a rule it is given a score at the end we add up the score and if it reaches a certain score we drop the email. Some of our rules include looking at subject phrases similar to those of known to carry malware, like Ransomware. We also monitor it if we see certain IPs being dropped, we add that IP to our firewall. The Master Spam filter server also looks for viruses in the email attachments. Finally, our primary server will go through a list of checks for Spam.
What file extensions do you block?
DK Systems aims to reduce risks to you and your company. There are some extensions that are associated with viruses and can cause great harm to your computer or worse your company. Really there is no real business reason for someone to send you the following files. By default we are blocking the following extensions in and out of the mail server.
.ADE, .ADP, .BAT, .CHM, .CMD, .COM, .CPL, .DLL, .DMG, .EXE, .HTA, .INS, .ISP, .JAR, .JS, .JSE, .LIB, .LNK, .MDE, .MSC, .MSI, .MSP, .MST, .NSH, .PIF, .SCR, .SCT, .SHB, .SYS, .VB, .VBE, .VBS, .VXD, .WSC, .WSF, .WSH, .CAB, .AIR, .APP, .CGI, .ESH, .GADGET, .JSX, .PL, .PS1, .PY, .PYC, .PYO, .REG, .RGS, .SCRIPT, .SCT, .UDF, .VBSCRIPT, .WS
Why is there a delay in receiving emails?
DK Systems incorporates a service called Greylisting, what this does is it tells the sender we are greylisting please try back in 60 seconds. Almost all email servers have a set time to resend the same message usually longer than 1 minute. Once they send a second time we add them to a list so the next time they send we can see they are a safe sender. Reason we do this, when a spammer sends out an email blast, they move on to the next spamming victim they do not see the reply to resend the email. Greylisting is an industry standard aimed at reducing Spam.
What if something happens to my account or the server will I still receive my email?
Most email servers allow you to set a retry setting. DK Systems servers will attempt up to 15 times to deliver, each time it retries its a little longer between attempts. The total time is over a four (4) day period, after that you will receive a notice that your message could not be delivered. We cannot verify how many times other servers attempt to retry, if they even do.
How big of an email can I receive?
DK Systems defaults the maximum sized email we will allow is 30 MB. If we allow anything bigger we run the risk of the file not coming in properly. Should the connection get disrupted on either the sender or our server the email may become corrupted.
How big of an email can I send?
DK Systems defaults the email size to 30 MB, we can increase if you need it. Just because we allow sending and receiving of an email this size you need to know what the receiver’s server will allow. Some servers only allow 5 MB. A future support document will show you how to utilize a service like Google Drive to send an email with a link to Google Drive in it. Our server will support other services and we will document them, as well.