Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
MTA
config(postfix)
postfix
postfix(x86-64)
server(smtp)
smtpd
smtpdaemon

Requires :

/bin/bash
/bin/sh
/bin/sh
/bin/sh
/bin/sh
/bin/sh
/bin/sh
/usr/bin/hostname
/usr/bin/openssl
/usr/sbin/alternatives
/usr/sbin/alternatives
/usr/sbin/groupadd
/usr/sbin/useradd
config(postfix) = 2:3.5.8-2.el8
diffutils
findutils
hostname
libc.so.6()(64bit)
libc.so.6(GLIBC_2.11)(64bit)
libc.so.6(GLIBC_2.14)(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.3)(64bit)
libc.so.6(GLIBC_2.3.2)(64bit)
libc.so.6(GLIBC_2.3.4)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libc.so.6(GLIBC_2.7)(64bit)
libcrypto.so.1.1()(64bit)
libcrypto.so.1.1(OPENSSL_1_1_0)(64bit)
libdb-5.3.so()(64bit)
libdl.so.2()(64bit)
libdl.so.2(GLIBC_2.2.5)(64bit)
libicudata.so.60()(64bit)
libicui18n.so.60()(64bit)
libicuuc.so.60()(64bit)
libnsl.so.2()(64bit)
libnsl.so.2(LIBNSL_1.0)(64bit)
libresolv.so.2()(64bit)
libresolv.so.2(GLIBC_2.2.5)(64bit)
libsasl2.so.3()(64bit)
libssl.so.1.1()(64bit)
libssl.so.1.1(OPENSSL_1_1_0)(64bit)
libssl.so.1.1(OPENSSL_1_1_1)(64bit)
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PartialHardlinkSets) <= 4.0.4-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rpmlib(PayloadIsXz) <= 5.2-1
rpmlib(ScriptletExpansion) <= 4.9.0-1
rtld(GNU_HASH)
systemd
systemd
systemd

Content of RPM :
/etc/pam.d/smtp
/etc/pam.d/smtp.postfix
/etc/postfix
/etc/postfix/access
/etc/postfix/canonical
/etc/postfix/dynamicmaps.cf
/etc/postfix/dynamicmaps.cf.d
/etc/postfix/generic
/etc/postfix/header_checks
/etc/postfix/main.cf
/etc/postfix/main.cf.proto
/etc/postfix/master.cf
/etc/postfix/master.cf.proto
/etc/postfix/postfix-files
/etc/postfix/postfix-files.d
/etc/postfix/relocated
/etc/postfix/transport
/etc/postfix/virtual
/etc/sasl2/smtpd.conf
/usr/bin/mailq
/usr/bin/mailq.postfix
/usr/bin/newaliases
/usr/bin/newaliases.postfix
/usr/bin/rmail
/usr/bin/rmail.postfix
/usr/lib/.build-id
/usr/lib/.build-id/05
/usr/lib/.build-id/05/0a672fe7e00ff27c560ab9ab3298d567926708
/usr/lib/.build-id/08
/usr/lib/.build-id/08/faabf5c7ef7374c59ba983ea9b85e577a1750c
There is 310 files more in these RPM.