Address = {address}

Address used by Receiver to receive messages.

Socket used for receiving messages is specified (either TCP socket, or UNIX socket ).

PoolOptions = {pool options}

Thread pool settings for Receiver.

RealClients = {logical}

Accept connections directly from clients.

ProcessingErrors = {action}

Action applied to messages when processing errors occur.

The parameter value can be one of the following actions:

tempfail, discard, reject.

Only one action can be specified.

StalledProcessingInterval = {time}

Timeout to process stalled messages.

Stalled messages are messages got by Receiver, but not processed in time and thus not sent to MailD core. That can happen when problems with network or power supply occur.

If a stalled message is found, Receiver queues it for processing.

OneCommandTimeout = {time}

Timeout to execute a single command.

OneMessageTimeout = {time}

Timeout to receive a single message.

AddReceivedHeader = {logical}

Adds a Received header to all received messages.

ReturnReject = {logical}

Receiver behaviour after the Reject action is applied to the message that is processed in the synchronous mode.

When the parameter value is set to Yes, the component returns SMTP 55* error. When the parameter value is set to No, the component returns successful SMTP 250 response, but the sender receives DSN (if not disabled).

The return response is extended with the Reply<Reason> string (the string is set in the settings of a plug-in which performed the reject action), but only if it is allowed by its UseCustomReply=Yes setting (where <Reason> is the reject action cause). Otherwise, the following standard message is output: "The message has been rejected by the Dr.Web MailD".

Note that if Dr.Web MailD is not operating in SMTP/LMTP proxy mode and is integrated with MTA, it is recommended to set the parameter value to No. This ensures correct notification of the sender if a message was rejected. Otherwise, if the parameter value is set to Yes, MTA can send notification on success before the message is checked and rejected.

If ReturnReject=No, it is recommended to specify an additional notify action (as during SMTP session Receiver, after rejecting a message, replies with 250 code that indicates successful message processing), or enable DSN (with the SkipDSNOnBlock parameter in the [Maild] section). But it is recommended to enable DSN only if the number of rejected messages is not large; otherwise, high load on MTA, which sends DSN, can occur.

GreetingString = {string}

Greeting line that is output on connection of a new SMTP client.

"%host%" macro is replaced with the Hostname parameter value from the [General] section.

"%ver%" macro is replaced with the current version of the drweb-receiver module.

RelayDomains = {Lookup}

List of domains that are allowed to relay messages.

If you specify a usual domain list, for which Dr.Web MailD is a mail relay, their subdomains are ignored. That is, mail arriving from their subdomains are not relayed.

It is possible to specify a list of subdomains by using regular expression or rfile.

Please note that the parameter value is Lookup.

Example:

RelayDomains = regex:.*.domain.com

Allows relaying to all domain.com subdomains.

Example:

RelayDomains = rfile:/path

rfile contains a list of regular expressions (Perl syntax), which must be specified one per line:

.*.domain.com

.*.domain1.com

.*.domain2.com

In the current version of Dr.Web MailD, the RelayDomains parameter does not support wildcard DNS records. Thus, expressions of this type are not allowed:

RelayDomains = *.domain

RestrictionStat = {logical}

Enables or disables statistics on SMTP restrictions (description of restrictions is provided below).

To get statistics, send SIGUSER1 signal to the drweb-receiver process. Statistics is stored in the restrictions.txt file in the directory defined in the BaseDir parameter from the [General] section.

DelayRejectToRcpt = {logical}

Suspends block of messages until RCPT stage, even if a restriction was applied before.

Setting this parameter allows working with outdated versions of email clients and output the list of blocked recipient addresses to the log file.

MaxRecipients = {numerical value}

Maximum number of recipients for one email message (number of RCPT TO commands).

When the parameter value is set to 0, maximum number of recipients is not limited.

If an IP address from which connection is established is marked as trusted, this restriction is not checked.

MaxConcurrentConnection = {numerical value}

Maximum number of concurrent SMTP connections from a single IP address.

When the parameter value is set to 0, maximum number of SMTP connections from a single IP address is not limited.

MaxMailsPerSession = {numerical value}

Maximum number of messages per single session (number of MAIL FROM commands).

When the parameter value is set to 0, maximum number of messages per single session is not limited.

MaxReceivedHeaders = {numerical value}

Maximum number of Received headers.

When the parameter value is set to 0, maximum number of Received headers is not limited.

Receiver always checks this restriction, even if an IP address is marked as trusted.

MaxErrorsPerSession = {numerical value}

Maximum number of errors per single session.

When the parameter value is set to 0, maximum number of errors per single session is not limited.

MaxMsgSize = {size}

Maximum message size (transmitted in DATA command).

Receiver always checks this restriction, even if an IP address is marked as trusted.

MaxJunkCommands = {numerical value}

Maximum number of RSET, NOOP and VRFY commands per session.

If this number exceeds the specified value, an error counter activates.

Current value of the error counter is set to 0 each time the message is successfully processed by the drweb-maild module.

If the parameter value is set to 0, this restriction is not checked.

MaxHELOCommands = {numerical value}

Maximum number of HELO, EHLO and LHLO commands per session.

If this number exceeds the specified value, an error counter activates. The score is reset after every successful processing of the message by drweb-maild.

If the parameter value is set to 0, this restriction is ignored.

SessionRestrictions ={restrictions list}

These checks are performed immediately after the connection was established (INTRO).

The following restrictions are checked:

•trust_protected_network

•trust_protected_domains

•trust_white_networks

•trust_white_domains

•reject_dnsbl

•reject_black_networks

•reject_black_domains

HeloRestrictions = {restriction list}

These checks are performed on HELO/EHLO session stage.

The following restrictions are checked:

•reject_unknown_hostname

•reject_diff_ip

SenderRestrictions = {restriction list}

Checks performed on FROM session stage.

The following restrictions can be checked:

•reject_unknown_sndrs

•reject_unknown_domain

•trust_sasl_authenticated

•pass_sasl_authenticated

RecipientRestrictions = {restriction list}

Checks performed on RCPT session stage. All recipients are checked in order they are declared.

The following restrictions can be checked:

•reject_unknown_domain

•reject_unauth_destination

•reject_unknown_rcpts

•pass_sasl_authenticated

DataRestrictions = {restriction list}

Checks performed on DATA stage of session.

The following restrictions can be checked:

•reject_spam_trap

•reject_multi_recipient_bounce

•pass_sasl_authenticated

BlackNetworks = {Lookup}

WhiteNetworks = {Lookup}

Network black and white lists.

These lists are used in trust_white_networks and reject_black_networks actions.

Syntax is similar to the one of the ProtectedNetworks parameter in the [Maild] section.

Please note that the parameter value is Lookup.

DNSBLList = {LookupLite}

DNSBL server list. This list is used in reject_dnsbl action.

Servers are checked one after another in the order they are specified in the parameter value until the message is blocked (upon the server response that the IP address is a "spammer") or the list ends.

Accessibility of the servers is checked by requesting them to resolve special IP address 127.0.0.2 (defined by the specification). The server must return positive response. Otherwise, the server is marked as unavailable, which is logged.

If no server responds to the request, the IP address is considered absent in the list of DNSBL servers, that is, the IP address is considered "clean".

Please note that the parameter value is LookupLite.

PositiveDNSBLCacheTimeout = {time}

Maximum time for caching positive responses from DNSBL servers.

NegativeDNSBLCacheTimeout = {time}

Maximum time for caching negative responses from DNSBL servers.

NegativeDNSCacheTimeout = {time}

Maximum wait time for caching negative responses from DNS servers.

Parameter value is valid for all responses from DNS servers except for those from DNSBL servers.

BlackDomains = {Lookup}

WhiteDomains = {Lookup}

Black and white lists of domains. These lists are used in trust_white_domains and reject_black_domains actions.

Syntax is similar to the one of the ProtectedDomains parameter in the [Maild] section.

Please note that the parameter value is Lookup.

SpamTrap = {LookupLite}

Spam trap address list.

This list is used in reject_spam_trap action.

Please note that the parameter value is LookupLite.

ProtectedEmails = {Lookup}

List of protected recipients' addresses.

It is used in reject_unknown_rcpts restriction. It allows to discard messages with invalid recipients (that are not in the list) and to resist DHA attacks (when used with anti_dha filter in Reputation IP Filter).

It is recommended to specify this parameter with reject_unknown_rcpts restriction and use it with anti_dha filter.

Please note that the parameter value is Lookup.

ProtectedSenderEmails = {Lookup}

List of protected senders' addresses.

It is used in reject_unknown_sndrs restriction. It allows to discard messages form invalid (unknown) senders and to resist DHA attacks (when used with anti_dha filter in Reputation IP Filter).

It is recommended to specify this parameter together with reject_unknown_sndrs and use it with anti_dha filter.

Please note that the parameter value is Lookup.

ReputationIPFilter = {filters list}

Reputation IP Filter settings.

Reputation IP filter allows assigning a score to the IP address according to the gathered statistics on connections as well as blocking this IP address temporarily if its total score is greater than some threshold value.

The following filters are available:

anti_dha, errors_filter, score_filter.

Filters are listed using comma as a delimiter, and are checked in order they were specified. For each filter, its name is specified first and then optional parameters are enumerated with a comma as a delimiter.

MaxSessionScore = {numerical value}

A threshold value for the general score of each session.

If this score exceeds the threshold value, the corresponding connection will be closed and a temporary error is returned.

If this value is set to 0, this parameter is ignored.