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documents:mail:mail-015

SPFレコードに登録されていないスパムホストへの対処例(Postfix)

2016/04/07
SPFレコードに登録されていないホストを制限する例。あくまで例なのでこれを参考にするなら自己責任で。

search?q=SPF%E3%83%AC%E3%82%B3%E3%83%BC%E3%83%89%E3%81%AB%E7%99%BB%E9%8C%B2%E3%81%95%E3%82%8C%E3%81%A6%E3%81%84%E3%81%AA%E3%81%84%E3%82%B9%E3%83%91%E3%83%A0%E3%83%9B%E3%82%B9%E3%83%88%E3%81%B8%E3%81%AE%E5%AF%BE%E5%87%A6&btnI=lucky

Postfix+postfix-policyd-spf-pythonの環境でのログ

さすがにさー、@ezweb.ne.jp はないよねー

Apr  6 23:31:55 noriko postfix/smtpd[25350]: warning: hostname abs-static-86.53.68.58.aircel.co.in does not resolve to address 58.68.53.86: hostname nor servname provided, or not known
Apr  6 23:31:55 noriko postfix/smtpd[25350]: connect from unknown[58.68.53.86]
Apr  6 23:31:57 noriko policyd-spf[25355]: None; identity=helo; client-ip=58.68.53.86; helo=abs-static-86.53.68.58.aircel.co.in; envelope-from=p0owpreq8i@ezweb.ne.jp; receiver=oreda@hgotoh.jp
Apr  6 23:31:57 noriko policyd-spf[25355]: Softfail; identity=mailfrom; client-ip=58.68.53.86; helo=abs-static-86.53.68.58.aircel.co.in; envelope-from=p0owpreq8i@ezweb.ne.jp; receiver=oreda@hgotoh.jp
Apr  6 23:31:57 noriko postfix/smtpd[25350]: 74507B62D02: client=unknown[58.68.53.86]
Apr  6 23:31:58 noriko postfix/cleanup[25356]: 74507B62D02: message-id=<>
Apr  6 23:31:58 noriko postfix/qmgr[25223]: 74507B62D02: from=<p0owpreq8i@ezweb.ne.jp>, size=1840, nrcpt=1 (queue active)
Apr  6 23:31:58 noriko postfix/local[25357]: 74507B62D02: to=<crowller@hgotoh.jp>, orig_to=<oreda@hgotoh.jp>, relay=local, delay=1.9, delays=1.9/0.01/0/0, dsn=2.0.0, status=sent (delivered to maildir)
Apr  6 23:31:58 noriko postfix/qmgr[25223]: 74507B62D02: removed
Apr  6 23:31:59 noriko postfix/smtpd[25350]: disconnect from unknown[58.68.53.86] helo=1 mail=1 rcpt=1 data=1 quit=1 commands=5

DNSのTXTレコードにあるSPF定義を見てみる

aircel.co.in のTXTレコードを見てみると、……spf.protection.outlook.comを追いかけてみたけど、まぁ該当のIPアドレスも範囲の定義にも見つからなかった。
だからSPFのStatusが Softfail になったのね。

root@noriko:/usr/local/etc/postfix # drill TXT aircel.co.in
;; ->>HEADER<<- opcode: QUERY, rcode: NOERROR, id: 32883
;; flags: qr rd ra ; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;; aircel.co.in.        IN      TXT

;; ANSWER SECTION:
aircel.co.in.   10800   IN      TXT     "v=spf1 ip4:58.68.109.187 ip4:202.148.202.47 ip4:202.148.202.54 ip4:58.68.109.188 include:spf.protection.outlook.com ~all"

;; AUTHORITY SECTION:

;; ADDITIONAL SECTION:

;; Query time: 132 msec
;; SERVER: 133.242.0.3
;; WHEN: Wed Apr  6 23:33:12 2016
;; MSG SIZE  rcvd: 163
root@noriko:/usr/local/etc/postfix #

whois でIPアドレスを調べてみる

住所が正しいならインドのあたりっぽい。 Dishnet Wireless limitedってプロバイダの顧客っぽいですねーこりゃ。

root@noriko:/usr/local/etc/postfix # whois 58.68.53.86

#
# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/whois_tou.html
#
# If you see inaccuracies in the results, please report at
# https://www.arin.net/public/whoisinaccuracy/index.xhtml
#

--- 中略 ---

% [whois.apnic.net]
% Whois data copyright terms    http://www.apnic.net/db/dbcopyright.html

% Information related to '58.68.53.80 - 58.68.53.87'

inetnum:        58.68.53.80 - 58.68.53.87
netname:        DWL-Idea
descr:          DWL-Idea-KOL
country:        IN
admin-c:        RM405-AP
tech-c:         RM405-AP
status:         ASSIGNED NON-PORTABLE
mnt-by:         MAINT-IN-DWL
changed:        rajesh.madhamshetti@aircel.co.in 20090927
source:         APNIC

person:         Rajesh Madhamshetti
nic-hdl:        RM405-AP
e-mail:         rajesh.madhamshetti@aircel.co.in
address:        Dishnet Limited
address:        19/32, Cathedral Garden Raod,
address:        Nungambakkam,
address:        Chennai
phone:          +91-44-42280000
country:        IN
changed:        rajesh.madhamshetti@aircel.co.in 20070306
mnt-by:         MAINT-IN-DWL
source:         APNIC

% Information related to '58.68.53.0/24AS10201'

route:          58.68.53.0/24
descr:          Dishnet Wireless Limited
origin:         AS10201
mnt-by:         MAINT-IN-DWL
changed:        rajesh.madhamshetti@aircel.co.in 20090109
source:         APNIC

% This query was served by the APNIC Whois Service version 1.69.1-APNICv1r0 (UNDEFINED)


root@noriko:/usr/local/etc/postfix #

リジェクトするホストを rejecthosts に定義する

/usr/local/etc/postfix/rejecthosts に58.68.53.80 - 58.68.53.87をREJECT対象として追加します。

58.68.53.80  REJECT
58.68.53.81  REJECT
58.68.53.82  REJECT
58.68.53.83  REJECT
58.68.53.84  REJECT
58.68.53.85  REJECT
58.68.53.86  REJECT
58.68.53.87  REJECT

seqコマンドで連番の文字列を作れば少し楽。

root@noriko:/usr/local/etc/postfix # seq -f '58.68.53.%g  REJECT' 80 87 >> rejecthosts

あとは postmap cdb:rejecthosts を実行して service postfix reload を実行して完了。

documents/mail/mail-015.txt · 最終更新: 2016/04/06 15:43 by k896951

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