The following options are available:

-6

enable IPv6. The default is equivalent to -4 . See also the IPv4 and IPv6 options in the flod file.

-4

disable IPv6. See also -6 .

-d

enables debugging output. Additional -d options increase the number of messages.

-V

displays the version of the DCC server daemon.

-b

causes the server to not detach itself from the controlling tty or put itself into the background.

-F

uses read() and write() instead of mmap() in some cases to access the DCC database. It is never the default.

-f

turns off -F .

-Q

causes the server to treat reports of checksums as queries except from DCC clients marked trusted in the ids file with rpt-ok . See -u to turn off access by anonymous or unauthenticated clients

-i server-ID

specifies the ID of this DCC server. Each server identifies itself as responsible for checksums that it forwards to other servers.

-n brand

is an arbitrary string of letters and numbers that identifies the organization running the DCC server. The brand is required, and appears in the SMTP headers generated by the DCC.

-h homedir

overrides the default DCC home directory, which is often /var/dcc .

-a Xo

[server-addr] [,server-port] adds an hostname or IP address to the list of local IP addresses that the server answers. Multiple -a options can be used to specify a subset of the available network interfaces or to use more than one port number. The default is to listen on all local IP addresses. It can be useful to list some or all of the IP addresses of multi-homed hosts to deal with local or remote firewalls. By default server-port is 6277 for DCC servers and 6276 for Greylist servers. It is the UDP port at which DCC requests are received and the TCP port for incoming floods of reports. If server-addr is absent and if the getifaddrs() function is supported, separate UDP sockets are bound to each configured network interface so that each DCC clients receives replies from the IP addresses to which corresponding request are sent. If is started before all network interfaces are turned on or there are interfaces that are turned on and off or change their addresses such as PPP interfaces, then the special string @ should be used to tell to bind to an IN_ADDRANY UDP socket. Outgoing TCP connections to flood checksum reports to other DCC servers used the IP address of a single -a option, but only if there is single option. Note that this means that -a 127.0.0.1 breaks flooding, often with "Invalid argument" messages. See also the flod file.

-I host-ID

changes the server's globally unique identity from the default value consisting of the first 16 characters of the host name. Host-ID is a string of up to 16 characters to be used instead of the first 16 characters of the system's hostname.

-q qsize

specifies the maximum size of the queue of requests from anonymous or unauthenticated clients. The default value is the maximum DCC RTT in seconds times 200 or 1000.

-t Xo

[type] ,threshold sets the threshold below which checksum reports are not sent or flooded to peer DCC servers. Checksums whose total counts are less than to the number threshold are not flooded. If threshold is the string "many," a value of millions is understood. It must be at least 10. If type is absent, only the thresholds for the body checksums are set. The thresholds built into for the body checksums, Body , Fuz1 , and Fuz2 are 20. The thresholds for the other checksums are so high by default that by themselves they can never cause reports to be flooded. The script commonly used to start sets the body thresholds to one third of in the dcc_conf file but no less than 10 or more than 20. That is the rejection threshold for dccm(8) , This threshold has no direct effect on which checksums are marked "bulk" by DCC clients. Instead, it allows cooperating DCC servers to share only the checksums of bulk mail and reduce inter-server communications. The thresholds should be larger than the number of addressees of typical private email but not much larger, because reports of checksums that total less than their thresholds can be flooded as many extra times as there are other thresholds. Reports containing any checksums marked "OK or "OK2" are not sent to other servers. This reduces the bandwidth needed for the inter-server flooding, the sizes of DCC database files, and helps protect the privacy of email of clients of a DCC server.

-G Xo

[on,] [weak-body,] [weak-IP,] [embargo] [,wait] [,white] changes to a Greylist server for dccm() or dccifd(8) . Greylisting consists of temporarily rejecting or embargoing mail from unfamiliar combinations of SMTP client IP address, SMTP envelope sender, and SMTP envelope recipient. If the SMTP client persists for embargo seconds and so is probably not an "open proxy," worm-infected personal computer, or other transient source of spam, the triple of is added to a database similar to the usual DCC database. If the SMTP client does not try again after embargo seconds and before wait seconds after the first attempt, the triple is forgotten. If the SMTP client persists past the embargo, the triple is added to the database and becomes familiar and the message is accepted. Familiar triples are remembered for white seconds after the last accepted mail message. The triple is forgotten if it is ever associated with unsolicited bulk email. All three durations can be a number of minutes, hours, days, or weeks followed by MINUTES , M , HOURS , H , DAYS , D , WEEKS or W . The default is -G 270seconds,7days,63days . The first duration or the embargo should be longer than open proxies can linger retransmitting. The second wait time should be as long as legitimate mail servers persist in retransmitting to recognize embargoed messages whose retransmissions were not received because of network or other problems. The white time should be long enough to recognize and not embargo messages from regular senders. Usually the DCC greylist system requires that an almost identical copy of the message be retransmitted during the embargo . If weak-body is present, any message with the same triple of sender IP address, sender mail address, and target mail address ends the embargo. If weak-IP is present, all mail from an SMTP client at an IP address is accept after any message from the same IP address has been accepted. Unlike DCC checksums, the contents of greylist databases are private and do not benefit from broad sharing. However, large installations can use more two or more greylist servers flooding triples among themselves. Flooding among greylist servers is controlled by the grey_flod file. All greylist cooperating or flooding greylist servers must use the same -G values. Clients of greylist servers cannot be anonymous and must have client-IDs and passwords assigned in the ids file. White- and blacklists are honored by the DCC clients. White-listed messages are embargoed or checked with a greylist server. The greylist triples of blacklisted messages, messages whose DCC counts make them spam, and other messages known to be spam are sent to a greylist server to be removed from the greylist database and cause an embargo on the next messages with those triples. Messages whose checksums match greylist server whitelists are not embargoed and the checksums of their triples are not added to the greylist database. The target counts of embargoed messages are reported to the DCC network to improve the detection of bulk mail.

-K Xo

[no-] type marks checksums of type (not) be "kept" or counted in the database unless they appear in the whitelist. The default is equivalent to -K no-all -K Body -K Fuz1 -K Fuz2 to count only the body checksums.

-T tracemode

causes the server to trace or record some operations. tracemode must be one of the following:

ALL

all tracing

ADMN

administrative requests from the control program, cdcc()

ANON

errors by anonymous clients

CLNT

errors by authenticated clients

RLIM

rate-limited messages

QUERY

all queries and reports

RIDC

some messages concerning the report-ID cache that is used to detect duplicate reports from clients

FLOOD

messages about inter-server flooding

IDS

unknown server-IDs in flooded reports

BL

requests from clients with IP addresses in the blacklist file.

The default is ANON CLNT .

-u anon-delay Ns [*inflate]

changes the number of milliseconds anonymous or unauthenticated clients must wait for answers to their queries and reports. The purpose of this delay is to discourage anonymous clients.. The anon-delay is multiplied by 1 plus the number of recent anonymous requests from an IP address divided by the inflate value. The string FOREVER turns off all anonymous or unauthenticated access not only for checksum queries and reports but also cdcc() stats requests. A missing value for inflate turns off inflation. The default value is 50,none , except when -G is used in which case FOREVER is assumed and required.

-C dbclean

changes the default name or path of the program used to rebuild the hash table when it becomes too full. The default value is libexec/dbclean in the DCC home directory. The value can include arguments as in -C '$DCC_LIBEXEC/dbclean -F' .

-L ltype,facility.level

specifies how messages should be logged. Ltype must be error or info to indicate which of the two types of messages are being controlled. Level must be a syslog() level among EMERG , ALERT , CRIT , ERR , WARNING , NOTICE , INFO , and DEBUG . Facility must be among AUTH , AUTHPRIV , CRON , DAEMON , FTP , KERN , LPR , MAIL , NEWS , USER , UUCP , and LOCAL0 through LOCAL7 . The default is equivalent to

-R Xo

[RL_SUB ,] [RL_ANON ,] [RL_ALL_ANON ,] [RL_BUGS] sets the four categories of rate-limits. RL_SUB limits the number of DCC transactions per second from subscribers or DCC clients with known client-IDs and passwords. This limit applies to each IP address independently. RL_ANON limits the number of DCC transactions per second from anonymous DCC clients. This limit applies to each IP address independently. It is better to use -u than to change this value to exclude anonymous clients. RL_ALL_ANON limits the number of DCC transactions per second from all anonymous DCC clients. Its default value is set by the compile-time value of DCCD_RL_ALL_ANON. This limit applies to all anonymous clients as a group, regardless of their IP addresses. RL_BUGS limits the number of complaints or error messages per second for all anonymous DCC clients as a group as well as for each DCC client by IP address. The default is equivalent to -R 200,50,200,0.1