Accepted Solutions
Hi Jacob,
1. DNS is not a 100% must while installing/running CUCM but there is
debate if this is a "best practice" or not
from the 9.x SRND
Domain Name System (DNS)
DNS enables the mapping of host names and network services to IP addresses within a network or networks. DNS server(s) deployed within a network provide a database that maps network services to hostnames and, in turn, hostnames to IP addresses. Devices on the network can query the DNS server and receive IP addresses for other devices in the network, thereby facilitating communication between network devices.
Complete reliance on a single network service such as DNS can introduce an element of risk when a critical Unified Communications system is deployed. If the DNS server becomes unavailable and a network device is relying on that server to provide a hostname-to-IP-address mapping, communication can and will fail. For this reason, in networks requiring high availability, Cisco recommends that you do not rely on DNS name resolution for any communications between Unified CM and the Unified Communications endpoints.
For standard deployments, Cisco recommends that you configure Unified CM(s), gateways, and endpoint devices to use IP addresses rather than hostnames. For endpoint devices, Cisco does not recommend configuration of DNS parameters such as DNS server addresses, hostnames, and domain names. During the initial installation of the publisher node in a Unified CM cluster, the publisher will be referenced in the server table by the hostname you provided for the system. Before installation and configuration of any subsequent subscribers or the definition of any endpoints, you should change this server entry to the IP address of the publisher rather than the hostname. Each subscriber added to the cluster should be defined in this same server table via IP address and not by hostname. Each subscriber should be added to this server table one device at a time, and there should be no definitions for non-existent subscribers at any time other than for the new subscriber being installed.
During installation of the publisher and subscriber, Cisco recommend that you do not select the option to enable DNS unless DNS is specifically required for system management purposes. If DNS is enabled, Cisco still highly recommend that you do not use DNS names in the configuration of the IP Communications endpoints, gateways, and Unified CM servers. Even if DNS is enabled on the servers in the cluster, it is never used for any intra-cluster server-to-server communications and is used only for communications to devices external to the cluster itself.
Deploying Unified CM with DNS
There are some situations in which configuring and using DNS might be unavoidable. For example, if Network Address Translation (NAT) is required for communications between the IP phones and Unified CM in the IP Communications network, DNS is required to ensure proper mapping of NAT translated addresses to network host devices. Likewise, some IP telephony disaster recovery network configurations rely on DNS to ensure proper failover of the network during failure scenarios by mapping hostnames to secondary backup site IP addresses.
If either of these two situations exists and DNS must be configured, you must deploy DNS servers in a geographically redundant fashion so that a single DNS server failure will not prevent network communications between IP telephony devices. By providing DNS server redundancy in the event of a single DNS server failure, you ensure that devices relying on DNS to communicate on the network can still receive hostname-to-IP-address mappings from a backup or secondary DNS server.
Unified CM can use DNS to:
•
Provide simplified system management
•Resolve fully qualified domain names to IP addresses for trunk destinations
•Resolve fully qualified domain names to IP addresses for SIP route patterns based on domain name
•Resolve service (SRV) records to host names and then to IP addresses for SIP trunk destinations
When DNS is used, Cisco recommends defining each Unified CM cluster as a member of a valid sub-domain within the larger organizational DNS domain, defining the DNS domain on each Cisco MCS server, and defining the primary and secondary DNS server addresses on each MCS server.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/9x/netstruc.html#wp1184840
And;
2. see below
Customer Impact from New Licensing Procedures
Cisco Unified Communications Manager on the Cisco UCS C210 Rack-Mount Server uses a different licensing model than Cisco Unified Communications Manager on an MCS server. The MAC address of the NIC card is no longer used to associate the license to the server.
Instead, the license gets associated to a license MAC, which is a 12 digit HEX value created by hashing the following parameters that you configure on the server:
•Time zone
•NTP server 1 (or "none")
•NIC speed (or "auto")
•Hostname
•IP Address (or "dhcp")
•IP Mask (or "dhcp")
•Gateway Address (or "dhcp")
•Primary DNS (or "dhcp")
•SMTP server (or "none")
•Certificate Information (Organization, Unit, Location, State, Country)
The ways to obtain the license MAC are as follows:
•Before installation, use the Answer File Generator (http://www.cisco.com/web/cuc_afg/index.html). When you generate the answer file, you also get the license MAC.
Note If you use this method, ensure that you enter the identical parameter values in the Answer File Generator and the Cisco Unified Communications Manager installation program, or the license will be invalid.
•After installation, navigate to Show > System in Cisco Unified Communications Manager Administration.
•After installation, use the CLI command show status.
Obtaining New Licenses
The process to redeem a Product Activation Key (PAK) for licenses at www.cisco.com/go/license is changed for a license MAC. When redeeming a PAK for a license MAC at this URL, you get prompted to select the type of license that you want to obtain:
•A physical MAC address — this is used when Cisco Unified Communications Manager will be installed on an MCS server.
•A license MAC address — this is used when Cisco Unified Communications Manager will be installed on Cisco Unified Communications Manager on the Cisco UCS C210 Rack-Mount Server.
After you make this selection, the generation and installation of the license file follows the same process.
Obtaining Rehosted Licenses When You Change License MAC Parameters
When you change any of the parameters that create the license MAC, the license that you obtained with it becomes invalid. You must request a rehosting of the license to obtain a valid license. The old license continues to work for a 30-day grace period.
To rehost your licenses, you must open a case with the licensing team. Contact the licensing team at licensing@cisco.com.
During the grace period, you can change the settings back to the licensed values to make your original license valid again. If you need more than 30 days of grace period, change your settings back to the licensed values, then change them back to the new values that you want to use. You will get another 30- day grace period.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/8_0_1/delta/vmware.html#wp1058262
Cheers!
Rob
"go easy...step lightly...stay free "
- The Clash
Hi Jacob,
1. DNS is not a 100% must while installing/running CUCM but there is
debate if this is a "best practice" or not
from the 9.x SRND
Domain Name System (DNS)
DNS enables the mapping of host names and network services to IP addresses within a network or networks. DNS server(s) deployed within a network provide a database that maps network services to hostnames and, in turn, hostnames to IP addresses. Devices on the network can query the DNS server and receive IP addresses for other devices in the network, thereby facilitating communication between network devices.
Complete reliance on a single network service such as DNS can introduce an element of risk when a critical Unified Communications system is deployed. If the DNS server becomes unavailable and a network device is relying on that server to provide a hostname-to-IP-address mapping, communication can and will fail. For this reason, in networks requiring high availability, Cisco recommends that you do not rely on DNS name resolution for any communications between Unified CM and the Unified Communications endpoints.
For standard deployments, Cisco recommends that you configure Unified CM(s), gateways, and endpoint devices to use IP addresses rather than hostnames. For endpoint devices, Cisco does not recommend configuration of DNS parameters such as DNS server addresses, hostnames, and domain names. During the initial installation of the publisher node in a Unified CM cluster, the publisher will be referenced in the server table by the hostname you provided for the system. Before installation and configuration of any subsequent subscribers or the definition of any endpoints, you should change this server entry to the IP address of the publisher rather than the hostname. Each subscriber added to the cluster should be defined in this same server table via IP address and not by hostname. Each subscriber should be added to this server table one device at a time, and there should be no definitions for non-existent subscribers at any time other than for the new subscriber being installed.
During installation of the publisher and subscriber, Cisco recommend that you do not select the option to enable DNS unless DNS is specifically required for system management purposes. If DNS is enabled, Cisco still highly recommend that you do not use DNS names in the configuration of the IP Communications endpoints, gateways, and Unified CM servers. Even if DNS is enabled on the servers in the cluster, it is never used for any intra-cluster server-to-server communications and is used only for communications to devices external to the cluster itself.
Deploying Unified CM with DNS
There are some situations in which configuring and using DNS might be unavoidable. For example, if Network Address Translation (NAT) is required for communications between the IP phones and Unified CM in the IP Communications network, DNS is required to ensure proper mapping of NAT translated addresses to network host devices. Likewise, some IP telephony disaster recovery network configurations rely on DNS to ensure proper failover of the network during failure scenarios by mapping hostnames to secondary backup site IP addresses.
If either of these two situations exists and DNS must be configured, you must deploy DNS servers in a geographically redundant fashion so that a single DNS server failure will not prevent network communications between IP telephony devices. By providing DNS server redundancy in the event of a single DNS server failure, you ensure that devices relying on DNS to communicate on the network can still receive hostname-to-IP-address mappings from a backup or secondary DNS server.
Unified CM can use DNS to:
•Provide simplified system management
•Resolve fully qualified domain names to IP addresses for trunk destinations
•Resolve fully qualified domain names to IP addresses for SIP route patterns based on domain name
•Resolve service (SRV) records to host names and then to IP addresses for SIP trunk destinations
When DNS is used, Cisco recommends defining each Unified CM cluster as a member of a valid sub-domain within the larger organizational DNS domain, defining the DNS domain on each Cisco MCS server, and defining the primary and secondary DNS server addresses on each MCS server.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/9x/netstruc.html#wp1184840
And;
2. see below
Customer Impact from New Licensing Procedures
Cisco Unified Communications Manager on the Cisco UCS C210 Rack-Mount Server uses a different licensing model than Cisco Unified Communications Manager on an MCS server. The MAC address of the NIC card is no longer used to associate the license to the server.
Instead, the license gets associated to a license MAC, which is a 12 digit HEX value created by hashing the following parameters that you configure on the server:
•Time zone
•NTP server 1 (or "none")
•NIC speed (or "auto")
•Hostname
•IP Address (or "dhcp")
•IP Mask (or "dhcp")
•Gateway Address (or "dhcp")
•Primary DNS (or "dhcp")
•SMTP server (or "none")
•Certificate Information (Organization, Unit, Location, State, Country)
The ways to obtain the license MAC are as follows:
•Before installation, use the Answer File Generator (http://www.cisco.com/web/cuc_afg/index.html). When you generate the answer file, you also get the license MAC.
Note If you use this method, ensure that you enter the identical parameter values in the Answer File Generator and the Cisco Unified Communications Manager installation program, or the license will be invalid.
•After installation, navigate to Show > System in Cisco Unified Communications Manager Administration.
•After installation, use the CLI command show status.
Obtaining New Licenses
The process to redeem a Product Activation Key (PAK) for licenses at www.cisco.com/go/license is changed for a license MAC. When redeeming a PAK for a license MAC at this URL, you get prompted to select the type of license that you want to obtain:
•A physical MAC address — this is used when Cisco Unified Communications Manager will be installed on an MCS server.
•A license MAC address — this is used when Cisco Unified Communications Manager will be installed on Cisco Unified Communications Manager on the Cisco UCS C210 Rack-Mount Server.
After you make this selection, the generation and installation of the license file follows the same process.
Obtaining Rehosted Licenses When You Change License MAC Parameters
When you change any of the parameters that create the license MAC, the license that you obtained with it becomes invalid. You must request a rehosting of the license to obtain a valid license. The old license continues to work for a 30-day grace period.
To rehost your licenses, you must open a case with the licensing team. Contact the licensing team at licensing@cisco.com.
During the grace period, you can change the settings back to the licensed values to make your original license valid again. If you need more than 30 days of grace period, change your settings back to the licensed values, then change them back to the new values that you want to use. You will get another 30- day grace period.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/8_0_1/delta/vmware.html#wp1058262
Cheers!
Rob
"go easy...step lightly...stay free "
- The Clash
