I have found the following two sites helpful in finding issues with the configuration of SSL secured web sites https://ssltools.digicert.com/checker/ https://www.ssllabs.com/ssltest/analyze.html Test which ciphers (TLS, SSL, etc) are enabled nmap -sV –script ssl-enum-ciphers -p 443 www.yourdomain.com Ref: https://nmap.org/nsedoc/scripts/ssl-enum-ciphers.html
Continue reading →Edit /opt/zimbra/maps/postfix_black_white_list Add the following entries # a comment 5.5.5.5 REJECT Stop sending me spam 4.4.4.0/24 REJECT All your servers are compromised fubar.com REJECT I want no email from anyone@fubar.com .fubar.com REJECT I dont want email from your subdomains either … Continue reading →
There are a couple of customizations that can only be done by editting the /opt/zimbra/postfix/conf/main.cf file. The problem is, if you do any upgrades, you loose your changes. After being burned by this, I added this script to my servers … Continue reading →
A user with an iPhone sends and email with an attachment to a recipient on a Zimbra server. The email is rejected and the following entry is made in the log: Mar 8 16:08:41 mx2 postfix/cleanup[20141]: 654AD251CD: reject: header Content-Type: … Continue reading →
zmprov ms `zmhostname` zimbraIPMode both /opt/zimbra/libexec/zmiptool zmcontrol restart Then update /etc/sysconfig/ip6ables and execute service ip6tables restart
Continue reading →By default, emails with an encrypted PDF or archive (i.e. zip) attachment will be blocked by Zimbra’s antivirus program, ClamAV. The user will be notified by an email titled ‘VIRUS (Heuristics.Encrypted.PDF) in mail FROM….’ with a message containing ‘A virus … Continue reading →
I found the following entries in my /var/log/messages file Feb 21 03:50:01 vm1 systemd: Created slice user-0.slice. Feb 21 03:50:01 vm1 systemd: Starting Session 6642 of user root. Feb 21 03:50:01 vm1 systemd: Started Session 6642 of user root. These … Continue reading →
Note: for Zimbra 8.6 and newer yum -y install epel-release yum -y install postgrey vim /etc/rc.d/init.d/postgrey find OPTIONS=”–unix=$SOCKET” replace with OPTIONS=”–inet=10023″ Centos 7 yum -y install epel-release yum -y install postgrey vim /etc/sysconfig/postgrey replace the line POSTGREY_OPTS=”–delay=60″ with POSTGREY_OPTS=”–delay=300 –inet=10023″ … Continue reading →
To view current sessions sh vpn-sessiondb remote (IPSec Remote VPN Clients) sh vpn-sessiondb l2l (L2L Tunnels) sh vpn-sessiondb svc (SSL VPN / Anyconnect Clients) sh vpn-sessiondb webvpn (Clientless sessions) sh ssh sessions (show users connected to ASA via SSH) To … Continue reading →
Firewalld is a pain to set up. To switch to iptables: yum -y install iptables-services If you would like to save the firewall rules you need to run the following command iptables-save > /root/iptables-rules.txt These rules can be added to … Continue reading →