標籤: centos

postfix郵件加上postgrey灰名單功能, 可擋下大部分廣告

技術

postfix郵件加上postgrey灰名單功能很簡單 , 步驟如下:

1. 安裝postgrey

CentOS 可於rpmfind.net找尋相對應的RPM版本安裝

Ubuntu 18.04 可直接安裝不用另外下載

sudo apt install postgrey

2. 找出啟動script的OPTIONS選項, 加上自動白名單功能, 與延遲120秒

centos 6:

vi /etc/rc.d/init.d/postgrey

—————————————————

OPTIONS=”–unix=$SOCKET –auto-whitelist-clients=5 –delay=120″

—————————————————

centos 7:

vi /var/lib/systemd/system/postgrey or

vi /usr/lib/systemd/system/postgrey.service

—————————————————

ExecStart=…

–auto-whitelist-clients=5

—————————————————

執行時候會長這樣

/usr/sbin/postgrey -d –unix=/var/spool/postfix/postgrey/socket –auto-whitelist-clients=5 –delay=120

3. 修改postfix的main.cf檔案, 加上check_policy_service unix:postgrey/socket

Centos:   vi /etc/postfix/main.cf

smtpd_recipient_restrictions =
permit_mynetworks,
permit_sasl_authenticated,
reject_non_fqdn_helo_hostname,
reject_non_fqdn_recipient,
reject_non_fqdn_sender,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
reject_unauth_destination,
reject_unauth_pipelining,
reject_invalid_hostname,
check_sender_access hash:/etc/postfix/sender_vip,
reject_rbl_client dnsbl.sorbs.net,
reject_rbl_client bl.spamcop.net,
reject_rbl_client cbl.abuseat.org,
check_policy_service unix:postgrey/socket

4. 產生報表

cat /var/log/maillog | postgreyreport  --nosingle_line --check_sender=mx,a --show_tries  --separate_by_subnet=":=================================================================\n"

2018/06/12 後記

這種作法經過實做, 不建議使用, 原因很簡單, 就是延遲的問題, 收個信會延遲, 這是非常麻煩的

雖然可以自動加入白名單, 但是有些不常聯絡, 一聯絡就要馬上收的狀況大有人在,

除非IT人員在公司很強大, 否則不要用這種方式

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GIT LFS 兩三事

技術

GIT 從1.8.2起, 為大家帶來了大檔案的解法.

這裡說一下GIT LFS 需要注意的兩三事:

  1. 你的本地端的GIT不需要所有LFS的檔案
    這樣可以解決clone過慢的問題, 本地端不需要於存放所有LFS歷史檔案.
  2. Git 2.3以前, 若要clone專案, 必須使用git lfs clone指令,否則使用git clone只會得到大檔案的指標, 並不是真正實體檔案. 但2.3 版本以後, 取消git lfs clone指令, 再度回歸 git clone 一樣可以取得大檔案的實體檔.
  3. CentOS LFS安裝要記得下 yum install git-lfs

asdf

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網站維護的管理策略

技術

網站, 終究面臨資訊安全的問題

咖啡偶提供簡單的管理策略

那就是安裝”網站代理伺服器proxy” , 任何要存取網站的行為, 都需請proxy存取真正的網站.

這樣一來, IT 只要定期更新proxy, 修補資安漏洞, 就不會因為真正的網站版本不一致或是有相容性問題, 導致後續維護困難, 例如:

老舊php 3網站,存在嚴重資安漏洞, 程式又因故無法升級,此時使用代理伺服器是好作法.

那款好用? 不外乎 apache httpd 或是 nginx 囉

想要深入了解或安裝httpd？請參考10004_(CentOS)apache httpd代理內部伺服器(proxy).txt

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postfix+dovecot+sasl+activate direcotory (centos 6)

技術 
1. vi /etc/dovecot/conf.d/10-auth.conf
uncommand the following setting
#!include auth-ldap.conf.ext
as
!include auth-ldap.conf.ext

2.  vi  /etc/dovecot/conf.d/auth-ldap.conf.ext
auth_username_format = %Lu

passdb ldap {
args = /etc/dovecot/dovecot-ldap.conf.ext

}

userdb static {
args = uid=501 gid=501 home=/home/vmail/%u
}
3. vi /etc/dovecot/dovecot-ldap.conf.ext
hosts = ad_server_ip
base = dc=test,dc=com,dc=tw
ldap_version = 3
auth_bind = yes
ldap_version = 3
auth_bind_userdn = test%u
pass_filter = (&(objectclass=person)(uid=%u))

ps. uid and gid must the same with postfix  and directory in linux server
ex: create one user “vmail”
user id is 501 , gid is 501

4. postfix’s main.cf
virtual_mailbox_domains = $mydomain
virtual_mailbox_base = /home/vmail/
virtual_mailbox_maps = ldap:/etc/postfix/ldap-users.cf
virtual_uid_maps = static:501
virtual_gid_maps = static:501
virtual_alias_maps = hash:/etc/aliases,ldap:/etc/postfix/ldap-aliases-inner.cf
#smtp auth
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
#additional param
message_size_limit = 40960000
smtpd_helo_required = yes
disable_vrfy_command = yes
strict_rfc821_envelopes = yes
bounce_queue_lifetime = 1d
maximal_queue_lifetime = 1d
data_directory = /var/db/postfix
header_checks = regexp:/etc/postfix/header_checks
smtp_host_lookup = native, dns
…
5. vi /etc/postfix/ldap-users.cf
server_host = ad_server_ip
search_base = dc=test,dc=com,dc=tw
version = 3
query_filter = (&(objectclass=*)(mail=%s))
result_attribute = samaccountname #Account from DC
result_format = %s/Maildir/
bind = yes
bind_dn = cn=ldap,cn=Users,dc=test,dc=com,dc=tw
bind_pw = ldappassword

6. vi //etc/sysconfig/saslauthd
# Directory in which to place saslauthd’s listening socket, pid file, and so
# on. This directory must already exist.
SOCKETDIR=/var/run/saslauthd

# Mechanism to use when checking passwords. Run “saslauthd -v” to get a list
# of which mechanism your installation was compiled with the ablity to use.
#MECH=pam
MECH=ldap

# Additional flags to pass to saslauthd on the command line. See saslauthd(8)
# for the list of accepted flags.
FLAGS=”-O /etc/postfix/saslauthd.conf -c -r”

7. vi /etc/postfix/saslauthd.conf
ldap_servers: ldap://ad_server_ip:389/
ldap_search_base: dc=test,dc=com,dc=tw
ldap_auth_method: bind
ldap_version: 3
ldap_bind_dn: cn=ldap,cn=Users,dc=test,dc=com,dc=tw
ldap_bind_pw: ldappassword
ldap_filter: (sAMAccountName=%u)

8. vi /etc/postfix/ldap-aliases-inner.cf
server_host = ad_server_ip
search_base = dc=test,dc=com,dc=tw
#scope = sub
query_filter = (memberOf:1.2.840.113556.1.4.1941:=CN=%s,OU=aliases_inner,DC=test,DC=com,DC=tw)
result_attribute = mail
result_format = %s
version = 3
bind = yes
bind_dn = cn=ldap,cn=Users,dc=test,dc=com,dc=tw
bind_pw = ldappassword


			

		

		
		
			
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如何在CentOS 6 下安裝VPN SERVER(l2tp over ipsec with pre-shared key)
		
		
 
	
		技術	



	
		

			
		
					

			
如何在CentOS 6 下安裝VPN SERVER(l2tp over ipsec with pre-shared key)


1. 安裝openswan, ppp , libpcap-devel

直接用CentOS裏面即可


2. 安裝xl2tpd(1.2.8)(http://www.xelerance.com/services/software/xl2tpd/)

解開後進入該目錄,執行

make

此時已經可以看到xl2tpd這個檔案了

cp xl2tpd /usr/local/sbin/

mkdir /etc/xl2tpd

cp examples/xl2tpd.conf /etc/xl2tpd/

cp examples/ppp-options.xl2tpd /etc/ppp/options.xl2tpd (這是給以下ppp使用的 sample)


3. 安裝rp-l2tpd (彌補xl2tpd 1.2.4 無法完整編譯)

http://sourceforge.net/projects/rp-l2tp/

下載後解開,進入該目錄,後執行

./configure

make

cp handlers/l2tp-control /usr/local/sbin/

mkdir /var/run/xl2tpd

ln -s /usr/local/sbin/l2tp-control /var/run/xl2tpd/l2tp-control


4. xl2tpd 設定

修改/etc/xl2tpd/xl2tpd.conf

ip range = 您希望對方可以得到哪些ip

local ip = server 對內ip

ex:

[lns default]

ip range = 192.168.0.11-192.168.0.13

local ip = 192.168.0.1

require chap = yes

refuse pap = yes

require authentication = yes

name = LinuxVPNserver

ppp debug = yes

pppoptfile = /etc/ppp/options.xl2tpd

length bit = yes


5. 修改 /etc/ppp/options.xl2tpd

ms-dns = 內部ms dns的ip

ex:

ipcp-accept-local

ipcp-accept-remote

ms-dns 192.168.0.2

noccp

auth

crtscts

idle 1800

mtu 1410

mru 1410

defaultroute

debug

lock

proxyarp

connect-delay 5000


6. ipsec 設定(預先共用金鑰)


6.1 設定 psk (pre-shared-key)

vi /etc/ipsec.d/william.secrets

###############################

%any: PSK “your shared key”

server_ip: PSK “your shared key”

###############################


其中 server_ip 是您的server 對外ip,

“your shared key”是你的共用金鑰


6.2 vi /etc/ipsec.conf

#############################################

version 2.0 # conforms to second version of ipsec.conf specification


# basic configuration

config setup

# Debug-logging controls: “none” for (almost) none, “all” for lots.

# klipsdebug=none

# plutodebug=”control parsing”

# For Red Hat Enterprise Linux and Fedora, leave protostack=netkey

protostack=netkey

nat_traversal=yes

virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12

oe=off

# Enable this if you see “failed to find any available worker”

nhelpers=0


#You may put your configuration (.conf) file in the “/etc/ipsec.d/” and uncomment this.

#include /etc/ipsec.d/*.conf

conn L2TP-PSK-NAT

rightsubnet=vhost:%priv

also=L2TP-PSK-noNAT


conn L2TP-PSK-noNAT

authby=secret

pfs=no

auto=add

keyingtries=3

rekey=no

ikelifetime=8h

keylife=1h

type=transport

left=<你的對外ip>

leftprotoport=17/1701

right=%any

rightprotoport=17/%any


############################################

7. ppp 設定

vi /etc/ppp/chap-secrets

加上

william * test *


其中william 是帳號, test是密碼


8. 修改 /etc/rc.local , 加上


8.1 開啟nat,底下192.168.0.0是內部ip範圍(eth1是您的對外網卡)

iptables -t nat -A POSTROUTING -o eth1 -s 192.168.0.0/24 -j MASQUERADE


8.2 允許ip_forward

echo “1” > /proc/sys/net/ipv4/ip_forward


8.3 確認server是否自動啟動, 或是加在/etc/rc.local

/etc/rc.d/init.d/ipsec start

/usr/local/sbin/xl2tpd -D &


9. 重開機(reboot),確認是否完備


ps.

1.要驗證ipsec 請執行

ipsec verify

要記得看log,有時候會遇到不預期的情形,此時就可以看log解決

/var/log/secure

/var/log/message

2. 若還有問題,請嘗試以下設定

vi /etc/sysctl.conf

#########################################################

net.ipv4.conf.default.rp_filter = 0

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

net.ipv4.conf.all.log_martians = 0

net.ipv4.conf.default.log_martians = 0

net.ipv4.conf.default.accept_source_route = 0

net.ipv4.conf.all.accept_redirects = 0

net.ipv4.conf.default.accept_redirects = 0

net.ipv4.icmp_ignore_bogus_error_responses = 1

########################################################


測試環境

linux CentOS 6

kernel 2.6.32

—————————–

windows xp client


(一) 新增連線


1. 開始->設定->網路連線->新增連線精靈


2. 選擇連線到公司網路(使用指定撥號或是vpn)


3. 選擇虛擬私人網路連線


4. 輸入名稱(可以隨意選)


5. 輸入vpn server IP


(二) 修改設定


1. 找出此VPN連線的TCP/IP設定, 選進階設定, 拿掉”使用遠端網路的預設匣道”


2. 找出”預先共用金鑰”,然後輸入PSK(pre-shared key),請看上面步驟6的金鑰密碼

3. 若是xp, 請取消勾選”要求資料加密(如果沒有加密就中斷連線)”


這樣就可以了


日期 2011.07.18

william http://fromtw.blogspot.com

			

		

		
		
			
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