Postfix SMTP Rotating IP using IPTables Rumi, August 1, 2022 I got 5 Public IPs. i’m Gonna configure them, so Postfix can use multiple interfaces/ips for outgoing smtp connections. First we need creating Interface aliases for those 5 public IPs. In my system, using centos: # cd /etc/sysconfig/network-scripts/ # cp ifcfg-eth0 ifcfg-eth0:1 Edit ifcfg-eth0:1 # vi ifcfg-eth0\:1 DEVICE=eth0 <-- default device HWADDR=XX:XX:XX:XX:XX:XX ONBOOT=yes TYPE=Ethernet BOOTPROTO=none IPADDR=202.XXX.XX.2 <-- default eth0 IP address PREFIX=24 GATEWAY=202.XXX.XX.1 DNS1=202.XXX.XX.XX Change DEVICE and IPADDR parameters DEVICE=eth0:1 <-- device alias #1 HWADDR=XX:XX:XX:XX:XX:XX ONBOOT=yes TYPE=Ethernet BOOTPROTO=none IPADDR=202.XXX.XX.3 <-- IP alias #1 PREFIX=24 GATEWAY=202.XXX.XX.1 DNS1=202.XXX.XX.XX We can continue with next interfaces for IP aliases same way as mention above. when we were done, bring those IP aliases up. #ifup eth0:1 #ifup eth0:2 #ifup eth0:3 #ifup eth0:4 ...... next interfaces Check if interfaces is up #ifconfig eth0 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:XX inet addr:202.XXX.XX.2 Bcast:202.XXX.XX.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feb0:e91/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:598678 errors:0 dropped:0 overruns:0 frame:0 TX packets:26348 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:49088016 (46.8 MiB) TX bytes:7707579 (7.3 MiB) eth0:1 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:XX inet addr:202.XXX.XX.3 Bcast:202.XXX.XX.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:2 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:XX inet addr:202.XXX.XX.4 Bcast:202.XXX.XX.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:3 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:XX inet addr:202.XXX.XX.5 Bcast:202.XXX.XX.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 …… and so on There’s no particular configuration need to adjust in postfix. Now the iptables part.make sure your iptables support for statistic match module. # iptables -m statistic -h ...... ...... ...... statistic match options: --mode mode Match mode (random, nth) random mode: --probability p Probability nth mode: --every n Match every nth packet --packet p Initial counter value (0 <= p <= n-1, default 0) Next continue with iptables rule for rotating source IP addresses. # iptables -t nat -I POSTROUTING -m state --state NEW -p tcp --dport 25 -o eth0 -m statistic --mode nth --every 5 -j SNAT --to-source 202.XXX.XX.2 # iptables -t nat -I POSTROUTING -m state --state NEW -p tcp --dport 25 -o eth0 -m statistic --mode nth --every 5 -j SNAT --to-source 202.XXX.XX.3 # iptables -t nat -I POSTROUTING -m state --state NEW -p tcp --dport 25 -o eth0 -m statistic --mode nth --every 5 -j SNAT --to-source 202.XXX.XX.4 # iptables -t nat -I POSTROUTING -m state --state NEW -p tcp --dport 25 -o eth0 -m statistic --mode nth --every 5 -j SNAT --to-source 202.XXX.XX.5 # iptables -t nat -I POSTROUTING -m state --state NEW -p tcp --dport 25 -o eth0 -m statistic --mode nth --every 5 -j SNAT --to-source 202.XXX.XX.6 Related Administrations Configurations (Linux) CentOSiptablesPostfixRotating IPSMTP
Install Virtualbox 5.2/6.1 on Ubuntu 16 headless mode May 21, 2021 Install Prerequisites Before installing VirtualBox 5.2/6.1, please install these packages below if your systems don’t already have them installed…. sudo apt update sudo apt-get install gcc make linux-headers-$(uname -r) dkms Add VirtualBox Repository If you want to always get the latest versions of VirtualBox when they become available, you’ll want… Read More
Monitor Windows Service using Nagios (Icinga) December 8, 2011 On the Nagios Server edit the file /usr/local/nagios/etc/objects/windows.cfg: # vi /usr/local/nagios/etc/objects/windows.cfg Add the following to create a new service definition to monitor the process state of WinVNC.exe (VNC Server): # Create a service for monitoring the WinVNC.exe process # Change the host_name to match the name of the host you… Read More
Delete files older than 10 days using shell command October 28, 2023 find is the common tool for this kind of task : find ./my_dir -mtime +10 -type f -delete EXPLANATIONS ./my_dir your directory (replace with your own) -mtime +10 older than 10 days -type f only files -delete no surprise. Remove it to test your find filter before executing the whole command Src: https://stackoverflow.com/questions/13489398/delete-files-older-than-10-days-using-shell-script-in-unix Related Read More