No - changing the DNS server(s) or domain name using "setup" on a CX module does not require a reboot.
I just verified on one of mine by running through the process and adding a DNS server. The change applied and started working immediately without reboot required.
cx>setup
Welcome to Cisco Prime Security Manager Setup
[hit Ctrl-C to abort]
Default values are inside []
Enter a hostname [cx]: cx
Do you want to configure IPv4 address on management interface?(y/n) [Y]: Y
Do you want to enable DHCP for IPv4 address assignment on management interface?(y/n) [N]: N
Enter an IPv4 address [<redacted>]: <redacted>
Enter the netmask [255.255.255.0]: 255.255.255.0
Enter the gateway [<redacted>]: <redacted>
Do you want to configure static IPv6 address on management interface?(y/n) [N]: N
Stateless autoconfiguration will be enabled for IPv6 addresses.
Enter the primary DNS server IP address [<redacted>]: <redacted>
Do you want to configure Secondary DNS Server? (y/n) [n]: y
Enter the secondary DNS server IP address: <redacted>
Do you want to configure Local Domain Name? (y/n) [y]: y
Enter the local domain name [<redacted>]: <redacted>
Do you want to configure Search domains? (y/n) [n]: n
Do you want to enable the NTP service? [Y]: Y
Enter the NTP servers separated by commas [<redacted>]: <redacted>
Do you want to enable the NTP symmetric key authentication? [N]: N
Please review the final configuration:
Hostname: cx
Management Interface Configuration
IPv4 Configuration: static
IP Address: <redacted>
Netmask: 255.255.255.0
Gateway: <redacted>
IPv6 Configuration: Stateless autoconfiguration
DNS Configuration:
Domain: <redacted>
DNS Server:
<redacted>
<redacted>
NTP configuration:
<redacted>
CAUTION:
You have selected IPv6 stateless autoconfiguration, which assigns a global address
based on network prefix and a device identifier. Although this address is unlikely
to change, if it does change, the system will stop functioning correctly.
We suggest you use static addressing instead.
Apply the changes?(y,n) [Y]: y
Configuration saved successfully!
Applying...
Done.
Press ENTER to continue...
cx>show dns
Local domain:
domain <redacted>
Search domain:
DNS servers:
nameserver <redacted>
nameserver <redacted>
cx>
