ಁաܕSMTPϓϩΩγʹΑΔϝʔϧ ૹ৴ू໿ͱΩϡʔ᫔᫓ճආͷݕ౼ খా஌ԝ, ኍ઒༏, ۙ౻Ӊஐ࿕(GMOϖύϘ), ౢ٢ོ෉, ּݪٛߊ(۝भେֶ) ϚϧνϝσΟΞɺ෼ࢄɺڠௐͱϞόΠϧ (DICOMO 2021) γϯϙδ΢Ϝ — 2021-07-02

1. എܠͱ໨త 2. ఏҊख๏ͱ༧උ࣮ݧ 3. ֓೦࣮ূ 4. ·ͱΊͱࠓޙͷ՝୊ ໨࣍ Tomohisa Oda ID: @linyows ॴଐ: GMOϖύϘגࣜձࣾ ϗεςΟϯάࣄۀ෦

എܠͱ໨త Section 1

എܠͱ໨త ٻΊΒΕΔϝʔϧͷ҆ఆੑ΍ηΩϡϦςΟ • ϝʔϧ͸ґવͱͯ͠޿͘࢖ΘΕ͓ͯΓɺWebαʔϏεͷೝূ༻్ͳͲॏཁͳ໾ ׂΛ࣋ͭ • ϝʔϧϗεςΟϯάࣄۀऀ͸ϋʔυ΢ΣΞͷϦιʔεޮ཰ΛߴΊΔͨΊɺΞΧ ΢ϯτ΍υϝΠϯΛߴूੵԽ͠௿ίετʹͳΔΑ͏ʹ͍ͯ͠Δ • ·ͨSPAMϝʔϧૹ৴΍େྔૹ৴ͳͲʹΑΔϨϐϡςʔγϣϯ௿Լ͔Βϝʔϧ ഑ૹ஗ԆʹͳΒͳ͍Α͏౒ྗ͍ͯ͠Δ • ϝʔϧϗεςΟϯάࣄۀऀ͸ϝʔϧͷ҆ఆੑ΍ηΩϡϦςΟΛܧଓతʹ୲อ͠ ͳ͚Ε͹ͳΒͳ͍ 4

• άϩʔόϧIPv4ΞυϨε਺ͷ੍໿ʹΑΓɺ֎෦΁ͷϝʔϧૹ৴αʔό͸ͳΔ ΂͘ू໿͢Δߏ੒ എܠͱ໨త ϝʔϧૹ৴ʹ͓͚Δैདྷख๏ 5 Mail User Agent Mail Submission Agent Mail Transfer Agent Mail Delivery Agent Mail Transfer Agent (MX) Mail User Agent Mail Hosting 📧 👩💻 👨💻 133.54.XXX.XXX

ू໿ͨ͠ϝʔϧૹ৴αʔόͰϝʔϧૹ৴ΩϡʔΛ؅ཧ͢Δ͜ͱʹͳΔͷͰ໰୊ ͷ͋ΔΞΧ΢ϯτʹΑΓૹ৴Ωϡʔ͕٧·Δͱɺ໰୊ͷͳ͍ΞΧ΢ϯτʹ΋Ө ڹ͠ૹ৴஗Ԇʹͭͳ͕Δ͜ͱ͕ଟ͍ • ର޲ͷMTA͔ΒΈͯϨϐϡςʔγϣϯ͕௿͘ड৴ϨʔτΛ੍ݶ͞Εͨ৔߹ • ૹ৴αʔόͷIP͕͋ΔDNSBLʹొ࿥͞Εɺର޲ͷMTA͕ͦͷDNSBLΛར༻͠ ͍ͯͯड৴ڋ൱Λ͞Εͨ৔߹ ର޲MTAͷৼΔ෣͍มԽΛݕ஌͠ʹ͍͘ എܠͱ໨త ैདྷख๏ͷ՝୊ 6

7 Mail User Agent Mail User Agent Mail Hosting Mail Transfer Agent (MX) Mail Transfer Agent (MX) Mail Transfer Agent (MX) Mail Submission Agent Mail Transfer Agent Mail Delivery Agent Mail Transfer Agent (MX) Mail User Agent 📧 👩💻 👨💻 🧟 📧 📧 📧 📧 ✉ 🦠 ✉ 🎣 📧 📧 📧 📧 📧 📧 📧 📧 📧 💭 ❓ ❌ 👨🔧 🗑 ✉ 🎣 ✉ 🎣 Operation 133.5.XXX.XXX

ߴूੵϚϧνςφϯτܕͷϝʔϧϗεςΟϯάʹ͓͍ͯϝʔϧૹ৴αʔόͷߏ ੒ख๏Λݕ౼͢Δ • ར༻͢ΔάϩʔόϧIPΞυϨεΛݮΒ͢ • ໰୊ͷಛఆϝʔϧૹ৴ͷӨڹΛݶఆతʹ͢Δ • ո͍͠ϝʔϧૹ৴΍ର޲ͷMTAϨεϙϯεͳͲ໰୊ݕ஌ʹܨ͕ΔΑ͏ͳ৘ใ Λऔಘ͢Δ എܠͱ໨త ຊݚڀͷ໨త 8

ఏҊख๏ͱ༧උ࣮ݧ Section 2

• ϝʔϧૹ৴αʔόΛςφϯτຖίϯςφʹ෼཭͢Δ*1ઌߦݚڀΛࢀর • ίϯςφ͔Β֎΁ͷSMTP௨৴ΛಁաܕSMTPϓϩΩγʹసૹ͢Δ • ಁաܕSMTPϓϩΩγ͸MXϗετʹ઀ଓ͢Δ • ಁաܕSMTPϓϩΩγͰ͸SMTPͷίϚϯυ΍MXϗετ͔ΒͷϨεϙϯεͳͲ ΛϩάͳͲʹग़ྗ͢Δ ఏҊख๏ͱ༧උ࣮ݧ ಁաܕSMTPϓϩΩγͷఏҊ 10 *1: দຊ ྄հ, খా ஌ԝ (GMOϖύϘגࣜձࣾ ϖύϘݚڀॴ), ּݪ ٛߊ, ౢ٢ ོ෉ (۝भେֶ ৘ใج൫ݚڀ։ൃηϯλʔ), ۚࢠ ߊհ (۝भେֶ αΠ όʔηΩϡϦςΟηϯλʔ), ܀ྛ ݈ଠ࿠ (GMOϖύϘגࣜձࣾ ϖύϘݚڀॴ), Ԭଜ ߞೋ (۝भେֶ ৘ใج൫ݚڀ։ൃηϯλʔ)ʮਫ਼៛ͳղੳͱ੍ޚ͕ Մೳͳ ߃ৗੑͷ͋Δϝʔϧج൫ʯϚϧνϝσΟΞɼ෼ࢄɼڠௐͱϞόΠϧ(DICOMO2018)γϯϙδ΢Ϝ, pp. 1383 - 1389, July 2018

11 Mail User Agent Mail Hosting Mail Submission Agent Mail Delivery Agent Mail Transfer Agent (MX) Mail User Agent 👩💻 👨💻 Transparent SMTP Proxy Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Routing 📧 📧 📧 133.5.XXX.XXX

• ਖ਼ৗͳPost fi xѼʹϝʔϧΛૹΓଓ͚ɺ߹ΘͤͯSMTPͷԠ౴͕ۃ୺ʹ஗͍ mxtarpitѼʹϝʔϧΛૹΓɺड৴஗ԆΛൺֱͨ͠ ૹ৴αʔό ड৴αʔό ఏҊख๏ͱ༧උ࣮ݧ ϝʔϧૹ৴Ωϡʔ෼཭ʹΑΔ᫔᫓ͷӨڹ͕ݶఆ͞ΕΔ࣮ݧ 12 Benchmark Script Post fi x mxtarpit Post fi x Shared Separated Post fi x Post fi x

13 ϝʔϧड৴਺ͱ࣌ؒܦա

• ίϯςφͰૹ৴αʔόΛ෼ࢄ͠ͳ͕Β΋ग़ޱΛू໿͢Δ͜ͱͰɺςφϯτ෼ ཭ͱ࢖༻͢ΔάϩʔόϧIPΞυϨεΛݮΒ͢͜ͱͷཱ͕྆Ͱ͖Δ • ϝʔϧૹ৴Ωϡʔ͸ू໿͞Εͳ͍ͷͰΩϡʔ᫔᫓ΛճආͰ͖ɺΩϡʔ٧·Γ ͸ಛఆςφϯτʹݶఆͰ͖Δ • ૹ৴઀ଓݩIP΍MXϗετͷϨεϙϯεϝοηʔδͳͲɺϝʔϧૹ৴ʹؔΘΔ ৘ใऩूʹΑΓո͍͠ৼΔ෣͍ͷΞΧ΢ϯτͷݕ஌ͱ੍ޚͰ͖ΔΑ͏ʹͳΔ ఏҊख๏ͱ༧උ࣮ݧ ಁաܕSMTPϓϩΩγʹΑΔԸܙ 14

֓೦࣮ূ Section 3

Output Log iptables • ಁաܕSMTPϓϩΩγ͸SMTPίϚϯυ΍MXϗετͷϨ εϙϯεΛϩάʹग़ྗ͢Δ • ϝʔϧૹ৴ίϯςφͱಁաܕSMTPϓϩΩγ͕ಉҰϗε τͰ͋ΔલఏͰͦͷؒͷ௨৴͸ฏจɺಁաܕSMTPϓϩ ΩγͱMXϗετ͸STARTTLSରԠΛ͢Δ • ͦͷͨΊɺϝʔϧૹ৴αʔόʹSTARTTLSΛඇରԠͱͯ͠ ϨεϙϯεΛॻ͖׵͑TLSμ΢ϯάϨʔυΛߦ͏ ϦϙδτϦ: https://github.com/linyows/warp ֓೦࣮ূ ϓϩτλΠϓͷ࣮૷ 16 Mail Transfer Agent (MX) Transparent SMTP Proxy Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Mail Transfer Agent Container Host

17 ϓϩτλΠϓ࣮૷ͷγʔέϯεਤ

2021/02/06 14:50:48 connected from 192.168.30.40:5749 3 2021/02/06 14:50:48 connected to 192.168.30.50:2 5 2021/02/06 14:50:48 <- 220 receiver ESMTP Postfix (Ubuntu)\r\ n 2021/02/06 14:50:48 -> EHLO sender\r\ n 2021/02/06 14:50:48 |< 250-receiver\r\n250-PIPELINING\r\n250-SIZE 10240000\r\n250-VRFY\r\n250-ETRN\r\n250-STARTTLS\r\n250- ENHANCEDSTATUSCODES\r\n250-8BITMIME\r\n250-DSN\r\n250-SMTPUTF8\r\n250 CHUNKING\r\ n 2021/02/06 14:50:48 <- 250-receiver\r\n250-PIPELINING\r\n250-SIZE 10240000\r\n250-VRFY\r\n250-ETRN\r\n250- ENHANCEDSTATUSCODES\r\n250-8BITMIME\r\n250-DSN\r\n250-SMTPUTF8\r\n250 CHUNKING\r\ n 2021/02/06 14:50:48 |> STARTTLS\r\ n 2021/02/06 14:50:48 >| MAIL FROM: SIZE=327\r\nRCPT TO: ORCPT=rfc822;root@receiver\r\nDATA\r\ n 2021/02/06 14:50:48 |< 220 2.0.0 Ready to start TLS\r\ n 2021/02/06 14:50:48 |> EHLO sender\r\ n 2021/02/06 14:50:48 pipe locked for tls connectio n 2021/02/06 14:50:48 |< 250-receiver\r\n250-PIPELINING\r\n250-SIZE 10240000\r\n250-VRFY\r\n250-ETRN\r\n250- ENHANCEDSTATUSCODES\r\n250-8BITMIME\r\n250-DSN\r\n250-SMTPUTF8\r\n250 CHUNKING\r\ n 2021/02/06 14:50:48 tls connected, to pipe unlocke d 2021/02/06 14:50:48 -> MAIL FROM: SIZE=327\r\nRCPT TO: ORCPT=rfc822;root@receiver\r\nDATA\r\ n 2021/02/06 14:50:48 <- 250 2.1.0 Ok\r\n250 2.1.5 Ok\r\n354 End data with .\r\ n 2021/02/06 14:50:48 -> Received: from sender (localhost [127.0.0.1])\r\n by sender (Postfix) with SMTP id 45B113EA9B\r\n for ; Sat, 6 Feb 2021 14:50:48 +0000 (UTC)\r\nFrom: \r\nTo: \r\nDate: Sat, 6 Feb 2021 14:50:48 +0000 (UTC)\r\nMessage-Id: \r\nSubject: Hi, Receiver from Sender\r\n\r\nXXXXXXXXXX\r\n.\r\nQUIT\r\ n 2021/02/06 14:50:48 <- 250 2.0.0 Ok: queued as 76DAD4113D\r\n221 2.0.0 Bye\r\ n 2021/02/06 14:50:48 connections closed ಁաܕSMTPϓϩΩγ͕ग़ྗ͢Δϩά

·ͱΊͱࠓޙͷ՝୊ Section 4

• ϝʔϧϗεςΟϯάʹ͓͚Δϝʔϧૹ৴ػೳͷ՝୊͸ɺ࢖༻͢ΔIPΞυϨεΛ ݮΒͨ͢Ίʹߦ͏ςφϯτू໿Ͱൃੜ͢Δϝʔϧૹ৴Ωϡʔͷ᫔᫓Ͱ͋Δ • ͦ͜Ͱϝʔϧૹ৴ू໿༻ͷಁաܕSMTPϓϩΩγΛఏҊͨ͠ • ϝʔϧૹ৴Ωϡʔͷ෼཭Ͱɺϝʔϧૹ৴஗ԆͷճආΛ֬ೝ͢Δ༧උ࣮ݧΛߦ ͳͬͨ • ϓϩτλΠϓ࣮૷ͱಈ࡞ݕূʹΑΓఏҊख๏ͷ֓೦͕࣮ূ͕Ͱ͖ͨ ·ͱΊͱࠓޙͷ՝୊ ຊݚڀͷ·ͱΊ 20

• ϝʔϧϗεςΟϯάʹ͓͍ͯ໰୊ͱͳΔΑ͏ͳৼΔ෣͍Λ͢ΔΞΧ΢ϯτΛ ݕ஌͢ΔͨΊʹ͸ɺಁաܕSMTPϓϩΩγͰऩू͢ΔMXϗετͷϨεϙϯε Ҏ֎ʹϨεϙϯεʹཁͨ࣌ؒ͠ͳͲ௥Ճͷ৘ใΛऔಘ͢Δඞཁ͕͋Δ • औಘͨ͠৘ใΛDatabaseԽ͠ΞΧ΢ϯτ΍υϝΠϯΛείΞϦϯά͢Δ͜ͱ Ͱɺར༻͢ΔάϩʔόϧIPΞυϨεΛ࢖͍෼͚Ͱ͋ͬͨΓɺ໰୊͕ղܾ͞ΕΔ ·Ͱ௨৴ϨʔτΛԼ͛Δͱ͍ͬͨ͜ͱ͕Ͱ͖Δ • ·ͨɺର޲ͷMTA͔Βड৴੍ݶ͞Ε͍ͯΔ͜ͱͷݕ஌͕ՄೳͱͳΔ ·ͱΊͱࠓޙͷ՝୊ ࠓޙͷ՝୊ 21

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