Can you configure DNS on a 2610?

[d.anthony.hadley_2]

I'm replacing a Linksys cable modem router with a Cisco 2610 so I can segment the LAN. IOS is 12.07. The Linksys router is configured to point to a DNS server at the ISP. Is there a way to do that on the 2610? Or, is this step unnecessary as all the computers point to the DNS server at the ISP for DNS resolution?

Also, would, or should, I add the network of the ISP assigned IP address to the RIP routing networks?. Or, is the default gateway sufficient? It has one IP address and NAT is used.

[rajeshk200_2]

hai hadly ,

in 2610 u can configure dns server with "ip name-server "command .

but i feel ur requirement is not clearly mentioned .

pls give me brief on ur requirement.

regards,

rajesh

[d.anthony.hadley_2]

Thanks for the response. The existing router, a linksys cable modem router, is configure to point to a DNS server at the ISP. It does not do DNS resolution itself, just points to a DNS server located at the ISP, which does the resolution. The access to the internet for this LAN is through a cable modem. I want to replace the existing Linksys router with a Cisco 2610 and need to know how to configure it for DNS. It looks like that command will do it.

My second question is if I should add their, the ISP's, network address to my RIP routing process. Or will a default gateway to their network suffice? Thanks.

[thisisshanky]

Hello,

If you have a LAN with PCs and you plan to use DHCP for the PCs, you can configure a DHCP pool on the Cisco IOS running on the 2600 (will have to load the proper IOS to do this). The DHCP pool for a 192.168.1.0 /24 network will look like this.

ip dhcp pool LAN

network 192.168.1.0 /24

default-router 192.168.1.1

lease 3

dns-server

The 5th command specifies a DNS server (which is your ISP DNS server) to the DHCP pool. This will ensure that all PCs will directly go the ISP DNS server.

You could use "ip name-server" command on the router. But I dont think you will be able to resolve addresses from the PC, by pointing the PCs to the router as the DNS server, because I think, the router does not run DNS server service (port 53). THe command is just used for DNS queries initiated by the router itself. I could be wrong....coz I have not tried this myself.

Hope that helps~!

[d.anthony.hadley_2]

Well, this is one of my questions. Does the ip name-server command point to a DNS server, or does it try to resolve names itself? According to the Cisco command reference, it looks like it points to a DNS server. I believe that's what the dns-server command in the DHCP pool does, point the computers to a DNS server at the ISP, correct?

Any input on my second question? Should I put the ISP network in my RIP routing process?

[thisisshanky]

ip name-server just points to a DNS server. So if I ping from the router, ping www.yahoo.com, a DNS request is sent by the router to the DNS server specified in the name-server command. By default all DNS requests generated by the router are broadcasted to 255.255.255.255

Do you have many other routers in your network running RIP ? What do you mean by ISP's network ? Is this the network allocated to you for the outside segment connecting to the ISP ? It would be a good idea to add this network to RIP protocol, only if you have a device in this network, which needs to be managed or accessed. Even if you do not include this network, a default route injected into RIP should do the job of reaching this network.

Hope that helps!

[d.anthony.hadley_2]

Thanks for your first answer. That is what I was looking for. On the second, I only have one router. It connects to the cable modem, which in turn connects to the ISP. The cable modem is assigned a public IP address by the ISP, A.B.C.D. On the LAN side of the router I have two ethernet segments and am running RIP between them. Do I add the Network A.B.C.0 network to my RIP routing process? Or is a default route to the ISP, say ip default-network A.B.C.D(or ip default-gateway) good enough?

[Richard Burts]

I would think that you would NOT want to add network A.B.C.D to RIP (this would mean that you would sent routing updates to your ISP - which they do not want to receive). Defining a default rout and advertising it to your attached segments would be the better solution.

HTH

Rick