This guide assumes you have a working Postfix server and want it to sign with DKIM.
There are a few things we have to understand to make all of this work though, which require you to be familiar with DNS as well.
1.) Install OpenDKIM
apt install opendkim
systemctl enable opendkim
2.) Edit /etc/opendkim.conf
Syslog yes
SyslogSuccess yes
Mode&nbs........
If you plugin your phone to your computer and enable USB File Transfer/Allow on the phone side but the contents of your phone on the computer side are empty in the file manager, you probably don't have mtp-tools.MTP or media transfer protocol is the standard protocol that most phones use to communicate over USB to the computer.
Just do this to fix it and get access to your files:
apt install mtp-tools
After that you should be a........
Enable "cli" mode equivalent in JunOS
cli
Configure Mode
configure
So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure".
How Do You Apply Changes You've Made?
You can make all kinds of changes to the switch, but remember they are not........
It really seems limited in that it can mainly give you the things you would see on the physical unit such as load etc..
wget https://downloads.sourceforge.net/project/apcupsd/apcupsd%20-%20Stable/3.14.14/apcupsd-3.14.14.tar.gz?r=https%3A%2F%2Fsourceforge.net%2Fprojects%2Fapcupsd%2Ffiles%2Flatest%2Fdownload&ts=1598115866
tar -zxvf apcupsd-3.14.14.tar.gz
cd apcupsd-3.14.14
[root@somebox apcupsd-3.14.14]#
./conf........
This is the reason that I don't like the new ADATA USB drives such as the UV128/64GB or 128GB drives and other ones that look to be the same style (the green sliding USB connector).
They just don't work well from new and never work properly at any point.
[ 788.242463] usb 1-1.2: new high-speed USB device number 16 using ehci-pci
[ 788.339816] usb 1-1.2: New USB device found, idVendor=125f, idProduct=db8a
[ 7........
Install Errors on Version 12:
This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5
on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error.
*Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install.
What really causes this even though you successfully install........
The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs.
qemu-kvm command:
/usr/libexec/qemu-kvm -version
QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard
........
Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments.
Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
You get errors like below and see you have all question marks for the permissions if you go to /run/user/1000/gvfs
If you try to access the mounted share such as anything mounted as gvfs like an SSH share in your file manager you may get an error like this. It generally means an interruption in communication or a fault with gvfsd has caused it.
Solutio........
Aug 10 01:11:54 mailserver postfix/smtp[6180]: 020AE17C2BD1: to=, relay=none, delay=0.29, delays=0.28/0/0/0, dsn=5.4.4, status=bounced (Host or domain name not found. Name service error for name=gmail.con type=A: Host not found)
A user complained that their e-mails weren't being delivered but they actually made a small typo and used gmail.con so it wasn't working as expected of course........
Ithought I'd post this becuase there is some bad information out there. Some guides tell you to edit /etc/postfix/master.cf (-o smtp_bind_address=) but this doesn't work. The same guide also says if you don't change it there you end up changing the listening IP/bind interface which is also not true.
Here is a simple and effective way to change Postfix's sending/binding/outgoing IP address (very important for reverse DNS and so mail servers don't block you)........
Jul 3 22:12:17mailserver postfix/smtpd[6195]: fatal: no SASL authentication mechanisms
Jul 3 22:12:18mailserver postfix/master[4881]: warning: process /usr/libexec/postfix/smtpd pid 6195 exit status 1
Jul 3 22:12:18mailserver postfix/master[4881]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling
This only ever happens in my experience when the authentication method is actually Dovecot. Usually the problem........
The most common solution is to use the /etc/postfix/header_checks but this is a big problem.
Why is header_checks a problem? Because it does it to all mail whether incoming or outgoing and whether authenticated or not. We of course want as much header information for incoming as we can get for many reasons but many organizations want to secure and make their mail clients as secure as possible.
I adapted this solution to the client's custom config, they are configur........
relay=alt4.gmail-smtp-in.l.google.com. [74.125.136.26], dsn=4.0.0, stat=Deferred: 421-4.7.0 [ 10] Our system has detected an unusual rate of
This is strange because the mail server IP is not blacklisted anywhere and the IP itself has not been used for years and this server is clean and has only sent a few e-mails to gmail.com in its entire time.
I wonder if this is a legacy block on a whole range of IPs as punishment for others in the block........
On occassion and from a variety of networks and clients, Sent messages don't get saved.
I'm wondering if these log messages could be why:
May 3 14:16:39 mail.box postfix/smtpd[5195]: connect from 192.168.1.58
May 3 14:16:39 mail.box postfix/smtpd[5195]: SSL_accept error from 192.168.1.58: -1
May 3 14:16:39 mail.box postfix/smtpd[5195]: lost connection after CONNECT from 192.168.1.58
May 3 14:16:39 mail.box postfix/smtpd[5195]:........
This pops up when connecting the phone and it doesn't seem to charge. The phone keeps showing a status message every few seconds "Connected as a media device".
It's ridiculous why this phone doesn't just default as a simple USB Mass storage device.
Here's what I see in /var/log/messages:
Jan 30 18:51:27 QuadCoreAM2 kernel: [18038228.144046] usb 1-3: new high speed USB device using ehci_hcd and address 24
Jan 30 18:51:28 QuadCoreAM2 ke........
The size of the message you are trying to send exceeds a temporary size limit of the server. The message was not sent; try to reduce the message size or wait some time and try again. The server responded: 4.5.3 Error: too many recipients.
We set this in main.cf:
smtpd_client_recipient_rate_limit=0
We didn't specify it before and the default is said to be 0/unlimited and it still didn't change anything.........
I experienced this with CPanel's Exim after an auto-update (a Google of this error produces lots of complaints with few clear solutions). In this case I'll put the solution at the top.
Run /scripts/buildeximconf to rebuild the Exim config and it should be fine after that.
mail -vs "from test" user@dest.com < .bash_history
LOG: MAIN
cwd=/root 4 args: send-mail -i -v user@dest.com
LOG: MAIN
&........
Centos 5 Postfix and SPAMASSASSIN Tutorial
yum install spamassassin
chkconfig spamassassin on
vi /etc/mail/spamassassin/local.cf
##############
#required_hits 5
#report_safe 0
#rewrite_header Subject [SPAM]
#5 is the least restrictive (means only the most obvious SPAM is caught. 0 is obviously the most restrictive/sensitive and would have lots of false positives
require........
Basically you should always be 100% sure that whatever IPyour mail server sends out with has reverse DNS/PTR records. Remember that unless you own your IPs then you won't be able to set your own reverse DNS. Even if you were to create a reverse PTR record on your DNS servers it will be ignored. Reverse DNS is queried to pre-assigned DNS servers of your ISP, so therefore you'll need to contact your ISP/Colo/Hosting provider to do a reverse DNS entry.
If you don't have........
Create Cert & Key:
openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key
mkdir /etc/mailssl
chmod 700 /etc/mailssl
cp server.* /etc/mailssl
Postfix SSL config
Edit /etc/postfix/main.cf:
#SSL stuff
smtpd_tls_cert_file = /etc/mailssl/server.crt
smtpd_tls_key_file = /etc/mailssl/server.key
To make smtps w........
understanding /etc/aliases
*remember to apply changes you need to run "newaliases" after editing /etc/aliases
one thing I don't get is that it doesn't allow you to specify the whole e-mail address on the left-hand side
eg:
yourfullemail@domain.com: someotheremail@domain.com
postalias: warning: /etc/aliases, line 109: name must be local (if you try the above)
It works more like this:
your........
Basic Port ListingHopefully someone finds this useful or at least interesting.
http://www.sans.org/top20/#u9
Name Port Protocol Description
Small services ........