This shows the result of email connections from the outside world to our servers.
The light green area at the base of the chart signifies the proportion of connections from which we accept mail. All the remainder are refused for various reasons. As can be seen, there’s generally a larger proportion accepted during the working weekday than other times, but a particularly heavy spam run can either compress the green area (when we reject it) or expand it (when we accept those mails).
Currently, most of the rejects are for “technical” reasons – where the sender really isn’t playing by the rules of the various protocols. Our premium-rate customers have the capability of tuning filters specific to them; to the extent that this works in rejecting spam it would reduce the green area further. Of course, were the spam senders to reduce their efforts the green area would be much larger – so it isn’t really possible to say that either big or small is good.
| conn_ref | connections refused | When one of our servers is in an overload situation. Note that many spammers deliberately send to our secondaries; we don’t really care that they crowd each-other out. Our legitimate customers are unaffected. |
| conn_ref_ip | too many connections from a single IP address | Some spammers open many sessions in parallel. We only accept a few. |
| rdns_rej | Reverse DNS verify | The name for the host found from the connecting IP address does not have an IP address listed which matches the connection. |
| H_rej | unacceptable HELO name | Illegal character, IP address, “localhost”, or a name which isn’t a host matching the connecting IP address. |
| proto_err | SMTP protocol error | Bad syntax, or not waiting for our response before sending another command. |
| B-rej | bounce rejection | Accounts can be marked for refusing items with an empty From address in the envelope. Such items are used for automated processing and rejection messages (“bounces”, “NDR”s) and are usually wanted, except when a spammer has picked on your name as the From for a spam run….. |
| condrop | connection dropped by initiator | We insert delays in the SMTP conversation when we find something suspicious. Many spammers give up. |
| relay_rej | attempt to relay through us | Someone who isn’t our customer asking us to send mail on their behalf. |
| NU_rej | no such user | a mistyped name, a spammer trying names at random, or another company checking an alleged From address with us. |
| SV_rej | sender verify | The senders mail host doesn’t exist, or it says the sender doesn’t exist. |
| V_rej | virus payload | Our virus scanner detected a known virus or phish. We will not pass these. |
| A_rej | administrative reject | The sender IP has recently sent a virus, or similarly annoyed us. |
| Q_rej | quota reject | The account is over-quota. Q-trej is a temporary quota reject. |
| tmp_rej | temporary reject | We couldn’t contact a mail-exchanger for the alleged From address, to check it, or user is over-quota. |
| noMX | From address has no mail-exchanger | The From address is totally made-up. |
| BCrej | Body Content reject | The message contains spam URLs or other hazardous material |
| Udnsbl | DNS-based blocklist | A sender is on a customer-specified blocklist – set to reject, not just warn. |
| Uenvl | user filter on mail envelope | Reject on source IP, From-domain or specific From address. |
| SVin_ok | sender verify in | Remote site checking an alleged From address with us. |
| in | mail accepted | We found no reason to reject (includes mark-as-spam and deliver-to-spam-folder). |
For enquiries about our Email services, please contact sales@tidymail.co.uk
