static hostname in core switch

[netacaduser575395547]

Hi there

I have a vpn connection to connect a customer site to a servers. the site does not have a dns server. the core switch has the dhcp configued.

i have configured the following:

x.x.x.com 192.x.x.17
ip host x.x.com 192.x.x.18
ip host x.x.com 192.x.x.17
ip name-server 8.8.8.8

and dns-server (core ip) in the dhcp pool.

the clients do not go though the vpn. the source vlan ping is a success through vpn.

do i need to have domain name in the core? domain lookup? ive tried them but did'nt work. DNS ip in the pc is the core ip.

another question is that: the customer has a regular PC where windows server installed on it. can i install DNS service on it? customer has 2000 clients.

many thanks

[Flavio Miranda · Accepted solution]

@netacaduser575395547 

 The configuration you made turn the switch into a client DNS. The switch will use this information but not the clients behind it. 

In order IOS you could use the switch as DNS server with the command " ip dns server". I am not sure this feature still remains in newer IOS. 

You can take a look

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr/command/ipaddr-cr-book/ipaddr-i3.html#wp2450847126

And yes, you can use the PC with windows as DNS server. 

https://learn.microsoft.com/en-us/windows-server/networking/dns/quickstart-install-configure-dns-server 

[M02@rt37]

Hello @netacaduser575395547 

First, having a domain name configured on the core switch is not strictly necessary for client DNS resolution. However, enabling ip domain-lookup is crucial, as it allows the switch to resolve hostnames to IP addresses. Ensure that ip name-server is correctly set with a valid DNS server, such as 8.8.8.8 or another operational DNS server. If the core is acting as the DNS relay, verify that its configuration points to the correct upstream DNS server and that the DHCP pool includes dns-server 《core_IP》 so that clients receive it as their DNS resolver.

The ip host entries on the core are useful for hostname-to-IP mappings within the switch itself but do not help clients unless the core is explicitly used as their DNS server. If clients receive the core’s IP as the DNS server, ensure that the core can resolve external DNS queries properly by testing with commands like ping 《hostname》from the switch itself.

If the clients are not routing DNS queries through the VPN, check if split tunneling is enabled on the VPN. Split tunneling can route only specific traffic through the VPN, potentially bypassing DNS traffic. To ensure all client traffic, including DNS, goes through the VPN, disable split tunneling or explicitly include DNS traffic in the VPN policy.

[MHM Cisco World]

I will send you PM 

thanks 

MHM