Use Mailx to send emails using office 365

just something that came up while setting up a monitoring script using mailx, figured ill note it down here so i can get it to easily later when I need it 😀

Important prerequisites

  • You need to enable smtp basic Auth on Office 365 for the account used for authentication
  • Create an App password for the user account
  • nssdb folder must be available and readable by the user running the mailx command

Assuming all of the above prerequisite are $true we can proceed with the setup

Install mailx

RHEL/Alma linux

sudo dnf install mailx

NSSDB Folder

make sure the nssdb folder must be available and readable by the user running the mailx command

certutil -L -d /etc/pki/nssdb

The Output might be empty, but that’s ok; this is there if you need to add a locally signed cert or another CA cert manually, Microsoft Certs are trusted by default if you are on an up to date operating system with the local System-wide Trust Store

Reference – RHEL-sec-shared-system-certificates

Configure Mailx config file

sudo nano /etc/mail.rc

Append/prepend the following lines and Comment out or remove the same lines already defined on the existing config files

set smtp-auth-user=###[email protected]###
set smtp-auth-password=##Office365-App-password#
set nss-config-dir=/etc/pki/nssdb/
set ssl-verify=ignore
set smtp-use-starttls
set from="###[email protected]###"

This is the bare minimum needed other switches are located here – link


echo "Your message is sent!" | mailx -v -s "test" [email protected]

-v switch will print the verbos debug log to console

Connecting to . . . connected.
220 Microsoft ESMTP MAIL Service ready at Sun, 6 Aug 2023 22:14:56 +0000
>>> EHLO vls-xxx.multicastbits.local Hello []
250-SIZE 157286400
220 2.0.0 SMTP server ready
>>> EHLO vls-xxx.multicastbits.local Hello []
250-SIZE 157286400
334 VXNlcm5hbWU6
>>> Zxxxxxxxxxxxc0BmdC1zeXMuY29t
334 UGsxxxxxmQ6
>>> c2Rxxxxxxxxxxducw==
235 2.7.0 Authentication successful
>>> MAIL FROM:<###[email protected]###>
250 2.1.0 Sender OK
>>> RCPT TO:<[email protected]>
250 2.1.5 Recipient OK
>>> DATA
354 Start mail input; end with <CRLF>.<CRLF>
>>> .
250 2.0.0 OK <[email protected]> []
>>> QUIT
221 2.0.0 Service closing transmission channel 

Now you can use this in your automation scripts or timers using the mailx command


recipient="[email protected]"
subject="Log file from /etc/app/runtime.log"

# Check if the log file exists
if [ ! -f "$log_file" ]; then
  echo "Error: Log file not found: $log_file"
  exit 1

# Use mailx to send the log file as an attachment
echo "Sending log file..."
mailx -s "$subject" -a "$log_file" -r "[email protected]" "$recipient" < /dev/null
echo "Log file sent successfully."

Secure it

sudo chown root:root /etc/mail.rc
sudo chmod 600 /etc/mail.rc

The above commands change the file’s owner and group to root, then set the file permissions to 600, which means only the owner (root) has read and write permissions and other users have no access to the file.

Use Environment Variables: Avoid storing sensitive information like passwords directly in the mail.rc file, consider using environment variables for sensitive data and reference those variables in the configuration.

For example, in the mail.rc file, you can set:

set smtp-auth-password=$MY_EMAIL_PASSWORD

You can set the variable using another config file or store it in the Ansible vault during runtime or use something like Hashicorp.

Sure, I would just use Python or PowerShell core, but you will run into more locked-down environments like OCI-managed DB servers with only Mailx is preinstalled and the only tool you can use 🙁

the Fact that you are here means you are already in the same boat. Hope this helped… until next time

Solution – RKE Cluster MetalLB provides Services with IP Addresses but doesn’t ARP for the address

I ran in to the the same issue detailed here working with a RKE cluster

After looking around for a few hours digging in to the logs i figured out the issue, hopefully this helps some one else our there in the situation save some time.

Make sure the IPVS mode is enabled on the cluster configuration

If you are using :

RKE2 – edit the cluster.yaml file

RKE1 – Edit the cluster configuration from the rancher UI > Cluster management > Select the cluster > edit configuration > edit as YAML

Locate the services field under rancher_kubernetes_engine_config and add the following options to enable IPVS

        ipvs-scheduler: lc
        proxy-mode: ipvs


After changes

Make sure the Kernel modules are enabled on the nodes running control planes


Example Rancher – RKE1 cluster

sudo docker ps | grep proxy # find the container ID for kubproxy

sudo docker logs ####containerID###

0313 21:44:08.315888  108645 feature_gate.go:245] feature gates: &{map[]}
I0313 21:44:08.346872  108645 proxier.go:652] "Failed to load kernel module with modprobe, you can ignore this message when kube-proxy is running inside container without mounting /lib/modules" moduleName="nf_conntrack_ipv4"
E0313 21:44:08.347024  108645 server_others.go:107] "Can't use the IPVS proxier" err="IPVS proxier will not be used because the following required kernel modules are not loaded: [ip_vs_lc]"

Kubproxy is trying to load the needed kernel modules and failing to enable IPVS

Lets enable the kernel modules

sudo nano /etc/modules-load.d/ipvs.conf


Install ipvsadm to confirm the changes

sudo dnf install ipvsadm -y

Reboot the VM or the Baremetal server

use the sudo ipvsadm to confirm ipvs is enabled

sudo ipvsadm


kubectl get svc -n #namespace | grep load
arping -I ens192
ARPING from ens192
Unicast reply from [00:50:56:96:E3:1D] 1.117ms
Unicast reply from [00:50:56:96:E3:1D] 0.737ms
Unicast reply from [00:50:56:96:E3:1D] 0.845ms
Unicast reply from [00:50:56:96:E3:1D] 0.668ms
Sent 4 probes (1 broadcast(s))
Received 4 response(s)

If you have the service type load balancer on a deployment now you should be able to reach it if the container is responding on the service

helpful Links

How to extend root (cs-root) Filesystem using LVM Cent OS/RHEL/Almalinux

This guide will walk you through on how to extend and increase space for the root filesystem on a alma linux. Cent OS, REHL Server/Desktop/VM

Method A – Expanding the current disk

Edit the VM and Add space to the Disk

install the cloud-utils-growpart package, as the growpart command in it makes it really easy to extend partitioned virtual disks.

sudo dnf install cloud-utils-growpart

Verify that the VM’s operating system recognizes the new increased size of the sda virtual disk, using lsblk or fdisk -l

sudo fdisk -l
Notes -
Note down the disk id and the partition number for Linux LVM - in this demo disk id is sda and lvm partition is sda 3

lets trigger a rescan of a block devices (Disks)

#elevate to root
sudo su 

#trigger a rescan, Make sure to match the disk ID you noted down before 
echo 1 > /sys/block/sda/device/rescan

Now sudo fdisk -l shows the correct size of the disks

Use growpart to increase the partition size for the lvm

sudo growpart /dev/sda 3

Confirm the volume group name

sudo vgs

Extend the logical volume

sudo lvextend -l +100%FREE /dev/almalinux/root

Grow the file system size

sudo xfs_growfs /dev/almalinux/root
Notes -
You can use this same steps to add space to different partitions such as home, swap if needed

Method B -Adding a second Disk to the LVM and expanding space

Why add a second disk?
may be the the current Disk is locked due to a snapshot and you cant remove it, Only solution would be to add a second disk/

Check the current space available

sudo df -h 
Notes -
If you have 0% ~1MB left on the cs-root command auto-complete with tab and some of the later commands wont work, You should clear up atleast 4-10mb by clearing log files, temp files, etc

Mount an additional disk to the VM (Assuming this is a VM) and make sure the disk is visible on the OS level

sudo lvmdiskscan


sudo fdisk -l

Confirm the volume group name

sudo vgs

Lets increase the space

First lets initialize the new disk we mounted

sudo mkfs.xfs /dev/sdb

Create the Physical volume

sudo pvcreate /dev/sdb

extend the volume group

sudo vgextend cs /dev/sdb
  Volume group "cs" successfully extended

Extend the logical volume

sudo lvextend -l +100%FREE /dev/cs/root

Grow the file system size

sudo xfs_growfs /dev/cs/root

Confirm the changes

sudo df -h

Just making easy for us!!

#Method A - Expanding the current disk 
sudo dnf install cloud-utils-growpart

sudo lvmdiskscan
sudo fdisk -l                          #note down the disk ID and partition num

sudo su                                #elevate to root
echo 1 > /sys/block/sda/device/rescan  #trigger a rescan
exit                                   #exit root shell

sudo lvextend -l +100%FREE /dev/almalinux/root
sudo xfs_growfs /dev/almalinux/root
sudo df -h

#Method B - Adding a second Disk 

sudo lvmdiskscan
sudo fdisk -l
sudo vgs
sudo mkfs.xfs /dev/sdb
sudo pvcreate /dev/sdb
sudo vgextend cs /dev/sdb
sudo lvextend -l +100%FREE /dev/cs/root
sudo xfs_growfs /dev/cs/root
sudo df -h


sudo lvmdiskscan
sudo fdisk -l
sudo vgs
sudo mkfs.xfs /dev/sdb
sudo pvcreate /dev/sdb
sudo vgextend almalinux /dev/sdb
sudo lvextend -l +100%FREE /dev/almalinux/root
sudo xfs_growfs /dev/almalinux/root
sudo df -h