Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)
The Mail Baby RBL is an IP blocklist (blacklist) that adds a penalty score to emails from junk sources instead of causing an outright block.
Updated on 17 Jun 2026: We updated this guide with the current SpamAssassin rule details and clearer automatic delisting guidance.
Summarize with
Check if you are listed on Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)
And 143 other blocklists.
Spamhaus
0Spam
Cisco
NoSolicitado
URIBL
abuse.ro
ALPHANET
Anonmails
Ascams
BLOCKEDSERVERS
Calivent Networks
EFnet
JustSpam
Kempt.net
NordSpam
RV-SOFT Technology
Scientific Spam
Spamikaze
SpamRATS
SPFBL
Suomispam
System 5 Hosting
Team Cymru
Validity
www.blocklist.de Fail2Ban-Reporting Service
ZapBL
2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamikazeSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftWhat is Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)?
The Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL) is an IP-based blocklist (blacklist) for the SpamAssassin email filtering platform. Its DNS zone is rblspamassassin.interserver.net. Unlike more aggressive blocklists that cause outright rejection of email, this list is intended for use in a scoring system. A receiving mail server checks the connecting IP during SpamAssassin evaluation and adds a small score when the lookup matches. Mail.baby describes this as a broad, automatically managed feed for IPs seen in spam traps, messages with very high spam scores, and other malicious activity. Listing and delisting are automated.
Who runs Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)?
This RBL is published by Mail.baby, a company that provides outbound email filtering, also called a smart host. Mail.baby's SpamAssassin rules include IP and URL DNS blocklists plus iXhash and reverse good-list rules. Its published guidance recommends scoring these signals inside SpamAssassin instead of rejecting mail solely because a blocklist or blacklist lookup matched.
How should receiving servers use this RBL?
Use this blocklist as one SpamAssassin network test, then choose a score that fits your filtering policy. Mail.baby's published example uses a 1.0 score for rblspamassassin.interserver.net and notes that the score should be lower than rbl.interserver.net because the SpamAssassin list is broader. A direct reject rule based only on this lookup increases false-positive risk.
SpamAssassin rule exampletext
header MAILBABY_RULE_SPAMMY_NETWORK rbleval:check_rbl('int', 'rblspamassassin.interserver.net.') describe MAILBABY_RULE_SPAMMY_NETWORK IP found in rblspamassassin spammy network list tflags MAILBABY_RULE_SPAMMY_NETWORK net score MAILBABY_RULE_SPAMMY_NETWORK 1.0
How do I get removed and delisted from Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)?
There is no manual delisting request process for this specific blocklist. Removals are handled automatically after the sending source stops matching the list's spam-trap, high-score, or malicious-activity signals. To be removed from this blacklist, fix the root cause first, then allow the automated process to age out the listing.
- Review SMTP and web server logs to identify the source of the spam. Common causes include compromised user accounts, malware, insecure web forms, abused mailing scripts, and authenticated SMTP misuse.
- Stop the unwanted mail before waiting for delisting. Reset affected mailbox passwords, remove malware, disable abused scripts, secure forms, and clear any queued spam so new samples do not refresh the listing.
- Check SPF, DKIM, and DMARC results for the sending domain after the abuse issue is fixed. Authentication will not directly remove the IP from this RBL, but broken authentication can compound filtering decisions at receivers.
- Wait for automatic removal after the spam has stopped. If more spam is seen, the timer resets and the IP stays listed or is relisted.
What's the impact of being listed on Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL)?
The impact of a listing on the Mail Baby Interserver SpamAssassin Realtime Blocklist (RBL) is low in most SpamAssassin scoring setups. The blocklist is designed to add score, not to reject mail by itself. Mail.baby's example SpamAssassin rule uses a 1.0 score. That score matters when the same message also has poor content signals, suspicious URLs, failed authentication, missing reverse DNS, a new or cold sending IP, or user complaint history. In those cases, the added blacklist score can push the final SpamAssassin score over the local spam threshold, causing junk placement or rejection.
