Enable mail relaying from a specific IP or range of IPs.
1. Exchange Management Console -> Server Configuration -> Hub Transport
2. New Receive Connector
* Set remote network to the IP or range you want to allow relay from (default is any IP so watch out here)
* “Externally Secured” authentication
* “Exchange Servers” permission group
* All other options disabled
If a (poorly coded) app reaches the maximum number of files or folders per directory in Linux, you may see errors like this:
Error happened when generating Download Link.
Please try again or Contact administrator.
(ERROR:mkdir)A quick and dirty way to increase the limit (and overall performance of the system) is to add the dir_index flag to the ext filesystem, then reindex:
tune2fs -O dir_index /dev/sda3
updatedb &This will set the ‘ADMIN’ user password back to default of ‘ADMIN’. You could set it to anything you want, this is just an example.
yum -y install ipmitool
modprobe ipmi_devintf
ipmitool -I open user set password 2 ADMINDon’t try to reinvent a complex and highly refined wheel, especially when customer data is involved. Please use phpass on any PHP project. (that’s PH-Pass)
http://www.openwall.com/phpass/
Good reading for password hashing in general.
wget http://layer1.rack911.com/before_apache_make -O /scripts/before_apache_make
chmod 700 /scripts/before_apache_make
## Rebuild apache (might want to do it thru WHM instead)
/scripts/easyapache --buildI’ve got a couple of Linux machines that are sitting outside of the Sflow ‘zone’ and AS traffic stats go unmeasured. I wanted to get a rough idea on the number of connections per AS number so here’s a little app that parses netstat and sorts AS numbers by number of connection.
NOTE1: This won’t work on Cpanel servers due to tmp restrictions.
NOTE2: Specify an alternative (e.g newer) GeoIPASNum.dat file with the –geo option.
wget http://djlab.com/stuff/asnum
chmod +x asnum
./asnumExample output:
[root@mx1 ~]# ./asnum
(18) | RFC1918 or BOGON
(11) | AS29889 Fast Serv Networks, LLC
(4) | AS3320 Deutsche Telekom AG
(2) | AS7922 Comcast Cable Communications, Inc.Quick and (very) dirty cron script
#!/bin.sh
#/root/doasnum.sh
#*/5 * * * * /root/./doasnum.sh >> /var/log/asnum.log
thedate=`date`
echo "***********************"
echo $thedate
/root/asnum
echo "***********************"Don’t forget to rotate the logs.
#/etc/logrotate.d/asnum
/var/log/asnum.log
{
rotate 7
daily
missingok
}There are 3 primary options:
1. Use PAR with PAR::Filter::Obfuscate or PAR::Filter::Crypto
2. Use Filter::Crypto::CryptFile (requires certain modules installed on target system)
3. Encrypt modules with Module::Crypt.
Update: 5/3/17 — Add additional notes for CentOS7 (dracut + grub2) and XenServer targets
All commands are run on new server.
1. Boot into rescue mode (iso, pxe, ect).
2. Create partitions with ‘fdisk /dev/sda’. Type 83 for non-RAID fs, 82 for swap, type fd in the case of RAID (all partitions). Flag boot partition as bootable.
In the case of SSD, add -S 32 -H 32 to the fdisk command and start the first partition on sector 2 for proper alignment.
If using RAID, duplicate the partition table after creating it on the first disk:
dd if=/dev/sda of=/dev/sdb bs=1 count=64 skip=446 seek=4462. Create RAID array (if applicable).
# For SSD, add: --chunk=128
mdadm --create /dev/md0 -e 0.90 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1 ## /boot
mdadm --create /dev/md1 -e 0.90 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2 ## Swap
mdadm --create /dev/md2 -e 0.90 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3 ## /3. Create filesystems
For spin disk:
mkfs.ext4 /dev/md0 # /dev/sda1 for non-RAID
mkfs.ext4 /dev/md2 # /dev/sda3 for non-RAIDFor SSD (non RAID):
mkfs.ext4 -b 1024 -E stride=128,stripe-width=128 -O ^has_journal /dev/sda1
mkfs.ext4 -b 1024 -E stride=128,stripe-width=128 -O ^has_journal /dev/sda3For SSD (RAID):
mkfs.ext4 -b 1024 -E stride=128,stripe-width=256 -O ^has_journal /dev/md0 ## stripe-width = stride x N disks
mkfs.ext4 -b 1024 -E stride=128,stripe-width=256 -O ^has_journal /dev/md2 ## stripe-width = stride x N disks4. Mount filesystems
mkdir /mount
mount /dev/md2 /mount ## /dev/sda3 for non-RAID
mkdir {/mount/boot,/mount/dev,/mount/sys,/mount/proc,/mount/tmp}
mount /dev/md0 /mount/boot ## /dev/sda1 for non-RAID5. Sync filesystems with Rsync over SSH (Ex: 1.2.3.4 is source machine)
rsync -aHxv --numeric-ids --progress root@1.2.3.4:/* /mount --exclude=/dev --exclude=/proc --exclude=/sys --exclude=/tmp
rsync -aHxv --numeric-ids --progress root@1.2.3.4:/boot/* /mount/boot --exclude=/dev --exclude=/proc --exclude=/sys --exclude=/tmp ## Only if /boot is on separate partition in source machineIf applicable: stop mysql on the source machine and resync the databases to prevent corruption:
rsync -aHxv root@1.2.3.4:/var/lib/mysql/* /mount/var/lib/mysql6. Update mdadm.conf
mdadm --examine --scan > /mount/etc/mdadm.conf7. Update fstab (if needed)
ls -la /dev/disk/by-uuid # to get new UUID's
vi /mount/etc/fstab8a. Install bootloader (CentOS5, CentOS6 / grub)
grub
root (hd0,0)
setup (hd0)
root (hd1,0) ## for RAID
setup (hd1) ## for RAID
exit8b. Install bootloader (CentOS7 / grub2)
Do step 10 (chroot) first, then this
grub2-install /dev/sda # Use correct device(s), repeat as neccesary
# Good time to clean up /etc/default/grub, then:
grub2-mkconfig -o /etc/grub2.cfg
# If migrating to Xen/XenServer:
dracut --add-drivers "xen-blkfront xen-netfront xen:vbd" --regenerate-all --force9. Optional: change IP address if both machines need to be online
vi /mount/etc/sysconfig/network-scripts/ifcfg-eth010. Hint: you can chroot into the cloned filesystem – for example – initramfs rebuilding:
cd /mount/
mount -t proc proc proc/
mount -t sysfs sys sys/
mount -o bind /dev dev/
chroot .11. Cross fingers, reboot
rebootFind all possible root symlinks (leftover from attempted exploits) and save them as a list ‘symlinks.txt’.
ls /var/cpanel/users | grep -v "\`\|\.\|cpanel\|root\|mysql\|nobody" | \
while read CPUSER; do find /home/$CPUSER -type l -not \( -lname "/home/$CPUSER/*" \
-o -lname "*rvsitebuilder*" -o -lname "[^/]*" -o -lname "/usr/local/apache/domlogs/*" \
-o -lname "/usr/local/urchin/*" \) ; done \
> symlinks.txt &This tool will poll the output of command(s) or URL(s), and send email alerts if the output changes, contains (or not contains) certain text, or becomes unavailable. It’s a light weight, reliable monitoring replacement for the pile of garbage most RAID vendors include with their cards. Complex excludes and finds can be specified as Perl regex patterns — useful for suppression various noise (RAID verify, ect). The default configuration includes examples that will monitor local LSI or Adaptec cards.
Note – Tested on CentOS only. if someone wants to try Alien on Debian please let me know how it works.
rpm -ivh http://djlab.com/stuff/cloud-mon-1.1-3.i686.rpmAfter installation, edit /etc/cloud.ini then:
service cloud-mon restartMake sure you have logrotate installed to prevent log growth. This package includes a simple logrotate script.