Sync Microsoft Domain Time To A Cisco NTP Device
KB ID 0001038 Problem I’ve been posting domain time articles for a long time, and on more than one occasion I’ve really needed to take my Windows time from a Cisco Device and failed miserably. I’ve even used third party NTP software to solve this problem on my own test network. On a client network, my colleague deployed ACS5 this week, I secured the ASA5585-X for AAA and it failed authentication. Logging revealed a...
Cisco ISE – Basic 802.1x With WindowsPart Four – Configuring The Windows Clients (Supplicants)
KB ID 0001083 Problem Back in Part Three we setup the switches ready to plug in our clients. I’m going to configure the Windows clients by Group Policy. But I suggest you carry out tests using single Windows clients and LOCAL policy until you know you have everything setup correctly. WARNING: Rolling this out without adequate testing, can resolve in all your Windows clients falling off the network Solution 1. On a DC or a...
Outlook Error 0x800CCC0F – Using POP3 To Exchange – Behind a Cisco CSC (Trend InterScan) Module
KB ID 0000642 Problem I upgraded a clients firewall and CSC software a couple of weeks ago, and ever since “some” users saw the following errors, Error 0x800CCC0F Task ‘{email address} – Sending’ reports error (0x800CCC0F): #The connection to the server was interrupted. If the problem continues, contact your server administrator or Internet service provider (ISP).’ Eventually it would time out...
Set Cisco ASA for Kerberos Authentication
KB ID 0000039 Problem You want to set up a Cisco ASA to authenticate users (VPN access for example). Solution Kerberos can only be used as an authentication protocol on the ASA, so its fine for allowing VPN connections but not for assigning policies etc. To work both the ASA and the domain need to be showing accurate time. Step 1: Set the ASA to get time from an External NTP Server 1. Log onto the ASA > Go to “Enable...
Cisco ASA – Only Allow Mail Servers SMTP Outbound
KB ID 0000172 Problem It’s not unusual for nasty Virus’s and Malware once they have infected a machine, to set up outbound communications on the mail protocol SMTP (TCP Port 25), which can lead to your public address being blacklisted. So it’s considered good practice to stop all your clients getting mail access outbound through your firewall, while still allowing your mail server. Note: On Cisco firewall’s,...
DNS resolves intermittently – EDNS Problems
KB ID 0000312 Problem DNS resolves intermittently, and your Exchange outbound mail may fail and give the following error: The following recipient(s) could not be reached: user@domain.com on (Date Time). There was a SMTP communication problem with the recipient’s email server. Please contact your system administrator. <(Domain.com) #5.5.0 smtp;550-Domain does not recognize your computer (xx.xx.xxx.xxx) as connecting from an...
Windows Server Setup RADIUS for Cisco ASA 5500 Authentication
KB ID 0000685 Problem Note: The procedure is the same for Server 2016 and 2019 This week I was configuring some 2008 R2 RADIUS authentication, so I thought I’d take a look at how Microsoft have changed the process for 2012. The whole thing was surprisingly painless. I will say that Kerberos Authentication is a LOT easier to configure, but I’ve yet to test that with 2012, (watch this space). Solution Step 1 Configure the...
Cisco AnyConnect – Securing with Microsoft Certificate Services
Part 1 (How to Configure Microsoft Certificate Services for AnyConnect) KB ID 0001030 Problem I’ve done a lot of AnyConnect deployments, and I’ve even done them with certificates in the past. I’ve seen plenty of articles and blogs that say ‘It would be better to use a PKI deployment like Microsoft Certificate Services’, but there’s very little info out there on how to set it up. I have a client...
AnyConnect – Using a Windows DHCP Server to Lease IP Addresses to the Remote Clients
KB ID 0001050 Problem I did an AnyConnect design for a client recently, and they asked ‘Instead of using the firewall to lease the DHCP addresses to our remote clients, can we use our Windows DHCP Server?” In the past I’ve used Windows DHCP servers for IPSEC VPN clients, but more recently I’ve tended to just use the firewall. The client had some valid reasons for wanting to do so, and given the complexity of...
AnyConnect Client Fails To Get IP From Windows DHCP Server
KB ID 0001053 Problem A few days ago I did an article on AnyConnect and Windows DHCP. I ran it up on the test bench for a client, and everything worked fine. Doing the install my test ‘remote’ client failed to get an IP address. As you can see the DHCP Server (Windows Server 2012 R2) is on a different network segment to the inside of the ASA. Solution 1. First this to do was debug the connection, ‘debug webvpn...