Skip to content
Skip to footer
Cisco.com Worldwide Home
Products & Services
How to Buy
Training & Events
Products & Services
Cisco Email Security Appliance
Obtain answers for frequently asked questions regarding your Cisco product.
View Documents by Topic
Choose a Topic
中文(中国) (Chinese Simplified)
What support resources and information are important to consider after purchase?
Can I swap hard drives between different Cisco Content Security Appliances?
Can a Message Filter divert messages to the Cisco Email Security Appliance (ESA) Spam Quarantine?
Can I whitelist or blacklist individual users via email addresses in the HAT?
Content Security Appliances FAQ: How do you perform a packet capture on a Cisco Content Security appliance?
Do internally generated messages such as alerts and notifications get scanned by filters, anti-spam, or anti-virus?
Does AsyncOS support IPv6 on the ESA?
Does Sophos Anti-Virus treat password protected Microsoft Office documents as encrypted?
Does adjusting the retention period on a system quarantine affect messages already in the quarantine?
ESA FAQ: Do I still need desktop anti-virus if I enable Sophos or McAfee Anti-Virus on my ESA?
ESA FAQ: Does the Ethernet MAC address in the configuration XML file cause problems in disaster recovery on the ESA?
ESA FAQ: How do I force a download of Sophos or McAfee Anti-Virus updates immediately?
ESA FAQ: How do you analyze intermittent mail delivery issues on the ESA?
ESA FAQ: How do you report Content Security Anti-Spam false positives or missed spam?
ESA FAQ: Outbreak Filters/Virus Outbreak Filters (VOF) FAQ
ESA FAQ: How do you specify multiple destination hosts with the alt-mailhost action?
HAT Delayed Rejection FAQ
How are SMTP authentication events logged?
How are emails blocked by rate limiting reflected in the logs?
How can I alter what ciphers are used with the Graphical User Interface (GUI)? Can I disable SSL v2 for the GUI?
How can I identify and address a mail loop situation on the ESA?
How can I prevent the backend infrastructure from being exposed in outbound messages?
How can a firewall or SMTP proxy affect ESMTP services?
How do I allow some messages from a sender with a low SBRS score, but block all other messages?
How do I blacklist or drop a sending domain using Incoming Mail Policy and Content Filter?
How do I bypass encryption in a content filter and DLP?
How do I configure a relay host on the ESA for outbound mail?
How do I configure the ESA to skip anti-spam and/or anti-virus scanning for my trusted senders?
How do I control body and attachment scanning in filters?
How do I create a content filter that applies to *all* incoming or outgoing mail ... ?
How do I decode the X-IronPort-AV header on the ESA?
How do I delete entries from the Recipient Access Table (RAT)?
How do I filter messages that are too large?
How do I find my Cisco Contract Number?
How do I keep copies of messages matched by my message filter?
How do I find the serial number of my Cisco Content Security Appliance?
How do I migrate from local spam quarantine on Cisco Email Security Appliance (ESA) to central spam quarantine on Security Management Appliance (SMA)?
How do I modify the subject header to flag messages that have a low SenderBase Reputation Score (SBRS)?
How do I monitor the health of the ESA?
How do I prevent my ESA from being used as an open relay?
How do I search and view the mail logs on the ESA?
How do I stop Bounce Verification from rejecting bounces on the ESA?
How do I stop duplicate disclaimer stamping?
How do I test Bounce Verification on the ESA?
How do I test a message or content filter to ensure it is working as designed?
How do I test if my domain supports TLS with CRES?
How do I test mail and network connectivity through an ESA using smtpping?
CRES FAQ: How do I use TLS to secure unencrypted CRES replies?
Why do messages get delivered even if SPF verification fails?
How do I write more efficient message filters?
How do you Whitelist a Trusted Sender?
How do you use LDAP Accept Query to validate the sender of relayed messages?
How do you use pscp on Microsoft Windows?
How does the Exception Table on the ESA work?
How to configure Virtual Gateways?
I have added the domain example.com to the WHITELIST sender group, why is it not working?
Is it possible to apply multiple certificates on an ESA and assign them to different interfaces or listeners?
Is there a filter condition matching on the file size of single attachment(s) instead of message size?
Is there a way to provide for failover or load balancing of LDAP servers?
Simple Mail Filter on How to Quarantine a Message
Unable to contact the update server to check for Sophos AntiVirus updates
What SMTP response codes does the ESA support?
What does "ICID lost" or "ICID close" mean?
ESA FAQ: What does the SBRS value of "none" mean, and how can you detect these scores?
What does the application fault 'shared/VTLStatus.py' mean?
What is Cisco Anti-Spam's catch rate, false-positive rate, and throughput?
What is UNIX mbox (mailbox) format?
What is the elapsed time for which the Cisco ESA reports outgoing domains?
What is the largest message size the Cisco ESA will accept?
What is the release terminology for content security?
(PDF - 67 KB)
What types of encryption does the encrypted() filter rule detect?
What's the difference between the Outbreak and Virus quarantines?
What's the shortest period of time you can configure Sophos Anti-Virus IDE updates?
When NIC pairing is configured, what conditions will trigger a failover?
ESA Default IP Address Determination with Multiple Interfaces on the Same Subnet
Which messaging platforms does the Cisco Email Security Appliance (ESA) support?
Why am I receiving an error when loading a Cisco Email Security Appliance (ESA) C350 configuration file to a C370?
Why are disclaimers in footer displayed as attachments?
Why are mail attachments bigger than the original file?
Why do you see XXXXXXXA after EHLO and "500 #5.5.1 command not recognized" after STARTTLS?
Why does the ESA accept and deliver mail messages containing bare < LF > characters?
Why is there no new version of AsyncOS shown when performing an upgrade?
ESA FAQ: How do I set up multiple company logos on ESA and CRES?
CRES FAQ: How do I correct the "This envelope is damaged and cannot be opened" error?
CRES FAQ: Why is my company logo not displayed in the encrypted envelope via CRES?
中文(中国) (Chinese Simplified)
执行升级时为何没有显示 AsyncOS 的新版本？
如何在 Microsoft Windows 中使用 pscp？
Microsoft Windows에서 pscp를 사용하려면 어떻게 해야 합니까?
업그레이드를 수행할 경우 AsyncOS의 새 버전이 표시되지 않는 이유는 무엇입니까?
9.5 and newer AsyncOS for Email Security upgrade with older certificates (MD5) communication TLSv1.2 to fail
CRES: SSL ciphers used
ESA FAQ: How to work with Cisco Email Submission and Tracking Portal
ESA FAQ: Troubleshooting Email Submission and Tracking Portal
ESA FAQ: What is a listener?
Enable service account (enablediag) via console on the ESA/WSA/SMA
How can I lock a user account in my domain in CRES?
How to generate license key file from PAK file for Cisco Email, Web Security Appliance and Security Management Appliance
How to install feature keys on a Cisco Email or Web Security Appliance
How to load the configuration on a replacement ESA and how to migrate it from one ESA to another?
How to modify the End-User Safelist/Blocklist on ESA
Requirements for the PVO Migration Wizard when ESA is clustered
Safelist/Blocklist limitation and configuration of limits
TLS Configuration Frequently Asked Questions for ESA
Web/Sender Base Network Participation (WBNP/SBNP)
What is the algorithm for certificate verification on the Cisco Email Security Appliance (ESA)?
Why are there network errors when the ESA communicates with the syslog server?
Why does the LDAP group query not work with Active Directory?
Why is the ESA handling DKIM authentication result permfail as hardfail?
All support information for
Cisco Email Security Appliance
Data Sheets and Literature
End-of-Life and End-of-Sale Notices
Consumer Packaged Goods
Materials and Mining
Sports and Entertainment
Meet our Partners
Find a Reseller
News & Alerts
Internet of Things (IoT)
Software Defined Networking (SDN)
Corporate Social Responsibility
Trust and Transparency Center
There's Never Been A Better Time
We Are Cisco
Cisco Designated VIP Program