Hi:
The problem is the following one: 
I have installed the SpamFilter, I can inside send electronic mail and outside my company, but when treatment to receive mail which they are outside my company, does not arrive any, in some cases bounces to its origin, the post office within my company if they arrive.

My server has installed Windows NT 4 and Exchange 5.5.

My file SPAMFILTER.INI has the following content:
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; a true after an ordb entry means their DNS is expecting the IP to be reversed
; i.e. to test a connection from 1.2.3.4 they expect 4.3.2.1.bl.spamcop.net
[blacklists]
site1=bl.spamcop.net, true
site2=sbl-xbl.spamhaus.org, true
site3=spam.dnsrbl.net, true
site4=dnsbl.njabl.org, true
site5=dnsbl.sorbs.net, true
;site6=dun.dnsrbl.net, true

[server settings]
; dns - your DNS server
dns=200.48.0.37

; SpamFilter can be limited to listen on one or more specific IPs. Leave empty for all IPs, or separate multiple IPs with a comma ","
ListenIP=
ListenFQDN=mail.zofratacna.com.pe
ListenPort=25

;The email address to use in Error Replies to senders
ErrorHandlerEmailAddress="Postmaster" <postmaster@zofratacna.com.pe>

; DestinationServer is where you want all mail received by SpamFilter to be forwarded to
DestinationServer=192.168.1.4
DestinationPort=25

; AllowPercent is used to accept (AllowPercent=1) or reject (AllowPercent=0) emails containing the % character.
; Many SMTP servers are susceptible to being tricked into relaying with this.
; Ex. if you are netwide.net, then a spammer can use
; mail to: joe%yahoo.com@netwide.net
; to relay mail to joe@yahoo.com if your server is vulnerable
; Setting AllowPercent to 0 rejects ALL recipients email addresses conatining the % sign
AllowPercent=0

;log daily activity to logfiles
Logging=1
ListenIP=
MultiThreaded=0
MaxInboundConnections=5000

;Set this to 1 if you want to disable EHLO extensions
DisableEHLO=0

;Any emails whose text portion exceeds this number of KB will not be scanned for keywords and Bayes
;Higher values *may* catch more spam but will cause higher load on processor
MaxMsgSizeForKeywordScan=64000

;Set RequireHELOBeforeMAILFROM to 0 if you do not want to require remote servers to issue a HELO or EHLO command before sending the email
RequireHELOBeforeMAILFROM=0

;Controls the minimum number of good and spam emails that must be received before the Bayesian filter kicks in
MinEmailsForBayesKickIn=5000

;by default SpamFilter will not allow any IP to relay thru it. Change DoNotTrustSelfByDefault to 1 if you want localhost to be able to relay
DoNotTrustSelfByDefault=1

;Remove any stale token in the corpus db.dat file that did not appear in incoming emails for the past n days
CleanUpCorpusIntervalDays=7

;Force disconnect of sessions after they have remained connected for this long
IdleDisconnectMinutesTimeout=15

;Force disconnect of sessions if a command has not been received within the last nn seconds
ReadTimeout=120

;if turned on, this will cause tokens in incoming emails being logged to screen with relevant probabilities
ShowBayesianTokens=0

;Set TagSPAMAndQuarantine=1 if you want to prefix every quarantine subject line with the prefix specified in SPAMTagPrefix ini parameter
TagSPAMAndQuarantine=0

;This SPAMTagPrefix will be prefixed to all subject lines marked for "mark as SPAM and deliver" along with the ation specified by TagSPAMAndQuarantine
SPAMTagPrefix=SPAM:

;Setting DoNotSendNDROnQuarantine to 1 will prevent generation of NDR when email are quarantined by causing SpamFilter *not* to send an error code when quarantining emails
DoNotSendNDROnQuarantine=0

;If turned on, the threads that save to disk and load into memory the bayes corpus tokens will have increased priority
BoostBayesPriority=1

;if TrailingSQLSemiColon is set to 1 SpamFilter will add a ";" to the end of SQL statements. Disable only to help solve problems with some databases.
TrailingSQLSemiColon=1

;If turned on, any quarantined (false positives) emails that the end user force-delivers will cause the sender to be automatically whitelisted
AutoWhiteListForceDelivery=1

;if EnableBadMailDir is set to 1, this will cause all emails that generate a "server error" when forwarded to your destination SMTP server will be saved in a "BadMailDir" for troubleshooting
;EnableBadMailDir=0
EnableBadMailDir=1

;if ScanReceivedHeaders is set to 1 SpamFilter will add the "Received:" headers to the text examined for keywords and statistical Bayesian searches.
ScanReceivedHeaders=1

;Number of hours SpamFilter will retry to deliver messages in queue to your destination SMTP server if it was unreacheable. Enter 0 to try forever until back online.
ExpireRetryQueueHours=0
AllowedDomainsFileName=C:Program FilesSpamFilterAllowedDomains.txt
ResponseWelcomeBanner=Bienvenido a ZOFRATACNA
LocalIPBlackListFileName=
ExcludedFromEmailsFileName=
LocalDomainsBlackListFileName=
KeywordsFileName=
WhiteKeywordsFileName=
ExcludedDomainsFileName=
AuthorizedTOEmailsFileName=
LocalEMailsBlacklistFileName=
LocalEMailsTOBlacklistFileName=
AttachmentsBlacklistFileName=
ExcludedEmailsFileName=
AutoWhiteListForceDeliveryFileName=AutoWhiteListForceDelivery.txt
TagSPAM=0
TagSPAMSubject=0
LogKeywords=0
AutoVersionCheck=1
DisableConnectionsGrid=0
SPFFilterEnable=1
SPFNeutralFilter=1
SPFSoftfailFilter=0
SPFFailFilter=0
RejectNoReverse=0
RejectNoReverseForceDelete=0
RejectEmptyMailFrom=1
RejectEmptyMailFromForceDelete=1
RejectSameToFrom=1
RejectSameToFromForceDelete=1
RejectSameToFromDomain=0
RejectSameToFromDomainForceDelete=0
BlackListForceDelete=1
ContentFilterForceDelete=0
LocalIPBlacklistForceDelete=0
LocalDomainsBlacklistForceDelete=0
CountriesForceDelete=0
LocalEmailsBlacklistForceDelete=0
LocalEmailsTOBlacklistForceDelete=0
AttachmentsBlacklistForceDelete=0
RememberStats=0
MaxRCPTTO=300
MinMAPS=10
MaxIncomingMsgSize=6144
MaxSubjectSpaces=10
FlushQueueInterval=60
ArchiveSpamDays=0
DeleteExpiredEmailInterval=60
BayesProbTrigger=276
EnableBayesianThread=1

; avoid being ourselves an open relay...
; enter here the recipient domains that SpamFilter will accept.
; I.E. if you are hosting netwide.net, then only emails addressed to user@netwide.net will
; be accepted and passed on to your DestinationServer.
; if your first entry is allow1=* then all emails will be accepted (not recommended)
; allow1=*

[Error Response]
ResponseBlacklistedMAPS=521 The IP %IP% is Blacklisted by %MAPSResponse%.
ResponseBlacklistLocalIP=521 The IP %IP% is Blacklisted.
ResponseBlacklistLocalDomain=521 The domain %Domain% is Blacklisted.
ResponseBlacklistLocalEMail=521 The EMail %EMailFrom% is Blacklisted.
ResponseBlacklistLocalEMailTo=521 The EMail %EMailTo% is Blacklisted.
ResponseNoReverseDNS=557 Your IP %IP% does not have a reverse DNS entry. Disconnecting...
ResponseMaxRCPTTO=557 You exceeded then maximum number of RCPT TO. Disconnecting...
ResponseCountryBlacklist=557 Your IP address is from a blacklisted country. Disconnecting..
ResponseRelayRestricted=557 You are not allowed to send mail to %EMailTo%
ResponseKeywordMatch=557 This email is rejected. It contains keywords rejected by the antispam content filter.
ResponseMaxIncomingMsgSize=552 This email is rejected. It exceeds the maximum allowed message size.
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Now, it must make some change in the DNS for the MX?

I wait for its quick answer.

Ivan Rojas.