我正在使用 Exim 並創建了一個可以接受和發送電子郵件的郵件伺服器。現在，我想為每封傳入的電子郵件啟用 SPF 檢查，以便將Received SPF標頭新增至這些電子郵件。但我似乎無法找出如何做到這一點的方法。
醫生說，SPF verification support is built into Exim if SUPPORT_SPF=yes is set in Local/Makefile. The support uses the libspf2 library https://www.libspf2.org/.
但我想如果他/她從原始程式碼建立 Exim，則只能將此選項設為 yes。我直接從 ubuntu 套件安裝它（我想 libspf2 是自動安裝的）並且不知道它的位置在哪裡Local/Makefile。我很確定這可以很容易地完成，但我現在對此一無所知。
30_exim4-config_check_rcpt我還檢查了 Exim 配置目錄，並在文件中找到了以下相關程式碼段。
spf-tools-perl這清楚地表明，如果啟用並安裝了SPF 檢查，Exim 將在 RCPT 命令之後檢查寄件者的 SPF 記錄。我安裝了spf-tools-perl，但仍然沒有看到任何Received SPF標題。所以，這就引出了兩個問題。
- 如何啟用 SPF 檢查以啟用此程式碼的執行？
- 為什麼 spf-tools-perl 正如文件明確指出的 Exim 使用 libspf。那為什麼要兩個庫呢？
# Use spfquery to perform a pair of SPF checks.
#
# This is quite costly in terms of DNS lookups (~6 lookups per mail). Do not
# enable if that's an issue. Also note that if you enable this, you must
# install "spf-tools-perl" which provides the spfquery command.
# Missing spf-tools-perl will trigger the "Unexpected error in
# SPF check" warning.
.ifdef CHECK_RCPT_SPF
deny
message = [SPF] $sender_host_address is not allowed to send mail from \
${if def:sender_address_domain {$sender_address_domain}{$sender_helo_name}}.
log_message = SPF check failed.
!acl = acl_local_deny_exceptions
condition = ${run{/usr/bin/spfquery.mail-spf-perl --ip \
${quote:$sender_host_address} --identity \
${if def:sender_address_domain \
{--scope mfrom --identity ${quote:$sender_address}}\
{--scope helo --identity ${quote:$sender_helo_name}}}}\
{no}{${if eq {$runrc}{1}{yes}{no}}}}
defer
message = Temporary DNS error while checking SPF record. Try again later.
!acl = acl_local_deny_exceptions
condition = ${if eq {$runrc}{5}{yes}{no}}
warn
condition = ${if <={$runrc}{6}{yes}{no}}
add_header = Received-SPF: ${if eq {$runrc}{0}{pass}\
{${if eq {$runrc}{2}{softfail}\
{${if eq {$runrc}{3}{neutral}\
{${if eq {$runrc}{4}{permerror}\
{${if eq {$runrc}{6}{none}{error}}}}}}}}}\
} client-ip=$sender_host_address; \
${if def:sender_address_domain \
{envelope-from=${sender_address}; }{}}\
helo=$sender_helo_name
warn
log_message = Unexpected error in SPF check.
condition = ${if >{$runrc}{6}{yes}{no}}
.endif```