Mail Baby Interserver Realtime Blocklist (RBL)
Mail Baby Interserver Realtime Blocklist is an IP-based blacklist (or blocklist) that automatically delists IP addresses after a five-day period.
Updated on 17 Jun 2026: We updated this guide with Mail.baby's RBL signals, automatic delisting behavior, and practical filtering guidance.
Summarize with
Check if you are listed on Mail Baby Interserver 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 Realtime Blocklist (RBL)?
The Mail Baby Interserver Realtime Blocklist (RBL) is an IP-based DNS blocklist, also called a DNSBL, for identifying IP addresses associated with spam or abusive network activity. Mail servers can query this blacklist while processing inbound email and use the result as a filtering signal. Mail.baby describes rbl.interserver.net as an automatic aggregated list built from multiple signals, including spam-trap hits across systems, brute-force login activity, and IPs blocked by Web Application Firewalls for malicious behavior.
The main operational details are:
- The DNS query zone is rbl.interserver.net.
- Listings are temporary. Mail.baby describes delisting as automatic after five days with no new activity from the IP.
- A listing can come from spam traps, brute-force attempts, Web Application Firewall blocks, or repeated abuse signals across systems.
- A basic test query uses 2.0.0.127.rbl.interserver.net, which corresponds to the test IP address 127.0.0.2.
Who runs Mail Baby Interserver Realtime Blocklist (RBL)?
The blocklist is operated by Mail.baby, an outbound email smart host service. Mail.baby routes outbound mail through zones based on filtering analysis and reputation data, and it monitors the reputation of its own sending IPs. That operating model explains why this RBL focuses on signals Mail.baby sees directly, including spam traps, abuse patterns, and network-level activity.
How should you use this RBL in filtering?
This RBL works best as one input in a spam score, not as the only reason to reject a message. Mail.baby's own guidance treats RBL hits as scoring signals. That matters because DNSBLs can include temporary or shared infrastructure, and a single IP listing does not prove every message from that IP is unwanted.
- Use a moderate score for rbl.interserver.net instead of an unconditional reject rule.
- Keep a local allow list for trusted senders and review it regularly.
- Log the DNSBL result, connecting IP, sender domain, and SMTP response so listings can be investigated later.
- Retest after fixing the source of abuse rather than repeating manual delisting requests, because this blacklist ages out automatically.
Example scoring ruletext
header MAILBABY_INTERSERVER_BLOCKLIST rbleval:check_rbl('int', 'rbl.interserver.net.') describe MAILBABY_INTERSERVER_BLOCKLIST IP appears on rbl.interserver.net block list tflags MAILBABY_INTERSERVER_BLOCKLIST net score MAILBABY_INTERSERVER_BLOCKLIST 2.0
How do I get removed and delisted from Mail Baby Interserver Realtime Blocklist (RBL)?
The Mail Baby Interserver Realtime Blocklist (RBL) does not provide a public manual delisting form. Removal is automatic, so the work is to stop the activity that caused the listing and then wait for the listing to expire.
Mail.baby describes the automatic delisting window for rbl.interserver.net as five days with no new activity from the IP. If the same IP keeps sending spam, hitting spam traps, triggering brute-force protections, or appearing in other malicious activity, the underlying signal has not stopped.
- Audit recent outbound mail logs for compromised mailbox accounts, leaked SMTP credentials, vulnerable web forms, and unexpected scripts.
- Check forwarding and mailing-list behavior so backscatter or replayed spam is not leaving through the same server.
- Separate shared-hosting users or customers that send high-risk traffic, especially when multiple domains share one outbound IP.
- Review SPF, DKIM, and DMARC alignment for domains using the IP. For domains you control, Suped's DMARC reporting product can help identify unauthorized sources and authentication failures before they create repeat blacklist (blocklist) listings.
- After remediation, query the DNSBL again and watch SMTP logs for continued rejection messages.
What's the impact of being listed on Mail Baby Interserver Realtime Blocklist (RBL)?
The impact of being listed on the Mail Baby Interserver Realtime Blocklist (RBL) is usually low to moderate rather than global. It affects mail where the receiving server checks rbl.interserver.net and chooses to score, quarantine, or reject based on that result. Large mailbox providers do not need to use this specific blacklist for it to matter, because smaller receivers and hosted mail systems can still reject mail at SMTP time.
Treat the listing as evidence of an operational problem, not just a delivery nuisance. A temporary DNS blocklist listing often points to compromised accounts, poor outbound controls, vulnerable web applications, or shared IP abuse. Fixing those issues reduces the chance of later listings on broader blocklists and blacklists.
