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Category File

Last updated September 2023

adaptive_backstore_leveldbuse LevelDB as the backing store for Adaptive Delivery
adaptive_backstore_riakset characteristics of the Riak backing store
adaptive_enabledenable or disable the adaptive module
adaptive_scopedefine the scope applicable to adaptive delivery (AD)
address_metrics_cleanse_intervalthe interval for refreshing address metrics
address_metrics_lifetimethe TTL of address metrics
alias_schemesenable named alias expansion schemes
allow_ip_literalallow IP addresses in email addresses
allow_null_envelope_senderallow the null envelope sender in e-mail addresses
allow_trailing_whitespace_in_commandspermit trailing whitespace at the end of an SMTP command
async_bounce_renderingwhich thread pool to use for bounce rendering
authorizationconfigure the console commands applicable to users
bind_addresssource address for outbound connections
bindingconfigure binding specific options
binding_auto_replumbenable or disable the auto replumber
binding_auto_replumb_intervalsets the time interval to check the plumbed state of statically plumbed bindings
binding_grouplogically group a set of bindings
blackholeblackhole mail
body_timeoutnetwork timeout once the DATA phase is complete
bounce_behaviorconfigure the action taken when a message is classified as a bounce
bounce_domainsconfigure the list of domains eligible for bounce processing by Momentum.
bounce_patternconfigure the pattern that inbound email addresses must match in order to be considered bounces.
bounce_suppress_listconfigure a list of email addresses that may not be considered original recipients.
bounces_inline_originalhow much of the original message to include in MDNs
capabilitiesselectively retain "root" capabilities
chrootchroot to a secure environment
clear_mail_queue_maintainersreschedule the mail queue maintainer
click_tracking_enabledenable or disable click tracking for SMTP injections
click_tracking_schemeset the hyperlink scheme to use for click tracking links in SMTP injections
cluster_max_outbound_connectionsset the maximum number of outbound connections for a scope and enforce it across a cluster
cluster_outbound_throttle_connectionslimit the rate at which connections are established, and enforce it across a cluster of systems
cluster_outbound_throttle_messageslimit the rate at which messages are delivered, and enforce it across the cluster
cluster_scope_max_outbound_connectionsprovide traffic shaping for outbound connections in a cluster configuration
cluster_server_max_outbound_connectionsset the maximum number of outbound connections, and enforce it across a cluster
connect_timeoutset the connection timeout
connect_timeout_to_delaytime interval before sweeping mail into the delayed queue
connection_allocation_aggressivenesstune the aggressiveness for establishing new connections to domains
contextuse to set arbitrary connection context key value pairs.
control_client_timeoutnetwork timeout for Momentum control client connections
crypto_engineenable hardware cryptography acceleration
crypto_lock_methodset the locking method used by the TLS layer
debug_flagsconfigure debug verbosity
default_bindingcontrol usage of the "default" binding
default_charsetcontrol usage of the "default" character set
delay_dsn_max_retry_intervalmaximum interval for sending DSNs to the sender of a message that has not yet been delivered
delay_dsn_retry_intervalbase interval for sending DSNs to the sender of a message that has not yet been delivered
delayed_binding_domain_fuzzlength of time to spread scheduled messages over when a bulk requeue is necessary
delayed_queue_scan_intervalhow often to call the maintainer for a domain
delivery_methodset the delivery method
delivery_poolassociate a pool of event loops with email delivery to use multiple threads
delivery_response_timeouttime to wait for a response to an outbound request
disable_nagle_algorithmdisable nagle algorithm on sockets
disk_queue_drain_ratecontrol the rate at which messages are spooled in on start-up
dns_cache_purge_intervalhow often the DNS response cache is scanned for stale entries
dns_expire_intervalhow often to check for domains with expired DNS information
dns_failures_to_purgeconfigure the maximum number of DNS lookups
dns_fallback_to_tcpwhether or not to fail over to TCP in place of UDP
domain_for_unqualified_recipient_addressesconfigure a domain which will be used to resolve delivery for unqualified addresses
domain_for_unqualified_sender_addressconfigure a domain which will be used to substitute for unqualified sender addresses
domainconfigure domain specific options
domainkeysenable or disable domainkeys signing
drop_body_after_trans_failnumber of retry attempts before freeing message memory
ecstream_portconfigure the port for ecstream deliveries
ecstream_timeoutthe amount of time to wait for an ecstream connection to be established
ehlo_hostnameset the hostname used for EHLO in outbound mail
ehlo_timeoutnetwork timeout for EHLO
enable_fbl_header_insertionenable or disable fbl header insertion
event_loopassociate a pool of event loops within a listener scope to use multiple threads
eventloopdefine a pool of event loops to enable multiple event loop configuration
events_per_iteremploy when using a concurrency greater than 1.
exclude_vctx_connexclude validation context keys from being journaled in the spool metadata.
exclude_vctx_messexclude validation context keys from being journaled in the spool metadata.
expensive_batch_assessmentonly treat messages as different if the headers are rendered differently
force_fsyncensure that data is synced to disk on reception
fully_resolve_before_smtpresolve all MX and A records before attempting delivery
gatewayconfigure a static SMTP route for mail
generate_bouncesgenerate MDNs if mail is failed after reception
generate_bounces_for_multi_recipient_policy_rejectionsgenerate MDNs after reception for policy rejections
generate_delay_dsngenerate DSNs if mail is delayed
growbuf_sizeThe size of an element in a growbuf chain
hostconfigure host specific options
hostnameoverride the system configured hostname
host_failure_retrytime to wait before attempting a retry
hot_domainslist of high-traffic domains that should be spread across maintainer threads
http_basic_authDefine the user credentials when using basic HTTP authentication
http_hostDefine the HTTP host
http_methodDefine the HTTP method to use
http_uriDefine the HTTP URI that you wish to connect to
http_versionDefine the HTTP version to use
idle_timeouttime to maintain idle outbound connections
inbound_throttle_messagesrate limit inbound mail
initial_hash_bucketsSet the number of hash buckets used by the system
inline_transfail_processinghow to handle transient failure processing
keep_message_dicts_in_memorypreserve memory representation of metadata when memory is low
large_message_thresholdConsider a message large when its size exceeds this amount
legacy_message_thresholdThe maximum size allowed for messages being passed to legacy modules
licensespecify an alternate license location
lmtp_portconfigure the port for LMTP deliveries
local_changes_filethe file for writing local configuration changes
local_changes_onlywhether there is a file for writing local configuration changes
mail_queue_check_vm_intervalhow often to apply memory management reduction on mail queues
mailerdaemonset the From: address for MDNs
mailfrom_timeouttimeout after MAIL FROM
maintainer_poolassociate a pool of event loops with mail queues, DNS lookup, and module events to use multiple threads
malloc2mmap_thresholduse mmap when allocations exceed this amount
masterdb_filespecify an alternate path for the statistics permastore
match_cache_lifeset the maximum number of seconds that the match cache will be valid
match_cache_sizethe size of the cache that holds the results of looking up matching scopes
max_deliveries_per_connectionmaximum number of messages to deliver before closing a connection
max_dns_ttlset the maximum DNS TTL
max_outbound_connectionsset the maximum number of outbound connections for a domain
max_recipients_per_batchmaximum number of recipients to send in a single outbound message transaction
max_request_sizemaximum size of an HTTP request
max_resident_active_queuethreshold above which messages are not held in memory
max_resident_messagesthreshold above which messages are not held in memory
max_resident_transfailsthe threshold for swapping transient failures out of memory
swap_out_meta_after_each_tempfailcontrols whether or not Momentum will update metadata such as num_retries, next_attempt, and message context on disk after each tempfail.
max_retriesoverride the system configured max_retries
max_retry_intervalmaximum retry interval
max_timed_events_per_iterthe maximum numer of timed events per scheduler iteration
mdn_failures_notifymailbox to which to send null recipient MDNs
memory_goalconfigure physical memory usage goal
memory_hwmconfigure physical memory usage high-water mark
message_expirationthe time to live for messages
migrate_connections_between_sibling_domainsoptimize connections for sibling domains
mime_parse_large_messages_during_receptionconfigure whether large messages are parsed upon reception or just in time.
min_dns_ttloverride DNS TTLs smaller than this value
mx_failures_fallback_to_aconfigure the maximum number of times an MX lookup will be attempted
mx_failures_to_delaynumber of consecutive failures before a domain is auto-delayed
never_attempt_expired_messagesNever attempt delivery of expired messages
never_retrywhether or not to retry delivery of failed messages
only_use_best_mx_for_relay_domainsIf this is set to true, only the lowest numerical priority MXs are used when sending to domains listed in bounce_domains or relay_domains.
open_relaywhether the MTA is an open relay or not
open_tracking_enabledenable or disable open tracking for SMTP injections
open_tracking_schemeset the hyperlink scheme to use for open tracking links in SMTP injections
opendkim_signwhether or not to enable OpenDKIM signing
outbound_throttle_connectionslimit the rate at which connections are established
outbound_throttle_messageslimit the rate at which messages are delivered
pathwaya grouping of inbound configuration options
pathway_groupa container for pathways
pcre_cache_sizeset the maximum size of the ec_pcre_compile cache
pcre_cache_ttlset the maximum TTL for the ec_pcre_compile cache
permastore_intervalthe frequency for saving various statistics
pidfileset the PID file path
prefer_ipv6_mxsprefer IPv6 addresses over ipv4 at a given mx priority level
prohibited_hostsprevent mail from being delivered to invalid destinations
rcptto_timeouttimeout after RCPT TO
relay_for_sending_domainsdomains that may use the MTA as a relay.
relay_domainsconfigure the list of domains for which Momentum relays mail
relay_hostsconfigure the list of hosts for which Momentum relays mail
remote_smtp_portset the port to be used for SMTP deliveries
require_ehloreject mail from clients that don't say HELO
reserve_maintenance_intervalhow often to perform mail queue maintenance
resolv_confspecify a custom resolv.conf
response_transcode_patternthe regex pattern for comparison to a server response
response_transcode_replacethe replacement string for a server response
retry_intervalbase retry interval
rfc2821_allow_whitespace_in_envelopepermit trailing whitespace before the final CRLF
rfc2821_pedantic_address_rulesAllow relaxation of enforcement of the rfc2821 address rules.
rfc2822_date_headerrfc2822 conformance
rfc2822_lone_lf_in_bodyrfc2822 conformance
rfc2822_lone_lf_in_headersrfc2822 conformance
rfc2822_max_line_lengthrfc2822 conformance
rfc2822_max_line_length_policydetermine how non-RFC-compliant line lengths are handled
rfc2822_messageid_headerrfc2822 conformance
rfc2822_missing_headersrfc2822 conformance
rfc2822_trace_headersrfc2822 conformance
rollup_mxMX Rollup enable/disable
rollup_mx_nameMX Rollup routing domain specification
routesconfigure message routing
rset_timeoutset the timeout after RSET
scope_max_outbound_connectionsprovide traffic shaping for outbound connections
scheduleroverride the default IO scheduler
securityScope for defining which permissions are retained by which user
send_8bitmimeEnable advertising of 8BITMIME when sending mail
server_max_file_descriptorssets the maximum number of file descriptors usable by the system
server_max_outbound_connectionssets the maximum number of outbound connections
server_reserve_outbound_connectionssets the server-wide connection limit reserve
signing_statscontrol how signing statistics are recorded
siv_throttle_cache_sizeset the maximum number of named throttles
skip_hostsskip the specified host, but consider other hosts in the domain
SNMPSimple Network Management Protocol Support
soft_bounce_drain_ratehow many soft bounces to place into the mail queues in a single scheduler iteration
spool_modeset the file mode for newly created spool files
spoolbaseset the base directory for the spool
ssl_lock_methodthe SSL lock method
starttls_injection_policyprotect against SMTP injections prior to TLS
supplemental_groupssecurity: supplemental groups to assume after startup
suspend_deliveryprevent outbound mail delivery
tcp_buffer_sizemaximum tcp buffer size for outbound connections
threadpoolconfigure thread pool specific options
timestampformatset the timestamp format used when logging to stderr
tlsdetermine whether to use TLS connection for outbound mail
tls_allow_renegotiationdetermine whether to enable TLS renegotiation
tls_cacertificate authority for outbound mail
tls_certificatecertificate to use for inbound and outbound mail
tls_ciphersspecify allowable ciphers for TLS inbound and outbound sessions
tlsv13_ciphersuitesspecify allowable TLSv1.3 ciphersuites for TLS inbound and outbound sessions
tls_client_cacertificate authority for inbound mail
tls_dhparams_filespecifies the file of Diffie Hellman (DHE) parameters that add per-session randomness to the encryption. Default parameters are built in the product if none are specified.
tls_enable_dhe_cipherscontrols whether or not Diffie Hellman (DHE) ciphers are available
tls_enginespecify the TLS library to use
tls_ifavailable_fallbackdetermine the behavior if TLS negotiation fails
tls_keyTLS key to use for outbound or inbound mail
tls_protocolsallowable ciphers for TLS inbound and outbound sessions
tls_verified_peer_is_authorizedMarks requests that use a verified SSL Client certificate as being authorized
tls_verifyspecify how to handle the remote presented certificate
tls_verify_modedetermine whether a TLS certificate is required
trace_smtp_modeset the default permissions of trace files
tracking_domainset the tracking domain to use for engagement tracking in SMTP injections
tracking_link_expiryset the expiration time for engagement tracking for SMTP injections
transfail_drain_ratethe maximum number of messages to pop off the transient failure queue in a single scheduler iteration
transform_8bitmime_contentEnable 8BITMIME downconversion when sending mail
unlink_on_spool_in_failureWhether or not to remove malformed messages
_unsafe_spoolallow dangerous spool semantics to be used
use_iflist_cacheWhether or not to cache the list of network interfaces configured by the system
use_ipv6Affects the selection of IPv6 hosts in the SMTP client
use_mmapuse mmap when spooling messages from disk
use_sendfileuse sendfile() when sending mail
usersecurity: user identity to assume after startup
xclientuse the xclient extension to SMTP for outbound mail

This chapter provides the definitions of the configuration options for the configuration files that are referenced in this document.

Most options that are common to Momentum 4 and Momentum 3 are documented in the Momentum 3.x Reference Manual. See the Configuration Options Summary .

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