Routers....

Do they have a definable default gateway parameter..... or is this only something that can be defined on a switch?

.....

Also can somebody please simplify (if/where possible) the difference between routed and routing. I think I have it clear in my head, but would like to get a more definitive explanation.

Thanks.

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Comments

blackninja

surfthegecko wrote: »

Do they have a definable default gateway parameter..... or is this only something that can be defined on a switch?

No this is for switches only, to set default gateway for remote management

surfthegecko wrote: »

Also can somebody please simplify (if/where possible) the difference between routed and routing. I think I have it clear in my head, but would like to get a more definitive explanation.

A routed protcol is the protocol that it's transported on: IP is the only one used these days

A routing protocol is the protocol that builds the routing table: RIP, OSPF, EIGRP for example

surfthegecko

thanks blackninja....much appreciated.

so if I set the int vlan 1 to: ip address 172.16.16.1 255.255.0.0
would the switches ip default-gateway just be on the same subnet eg 172.16.16.100 255.255.0.0

or is this not linked to the vlan interface.

amp2030

You can set a default route on your router though, of 0.0.0.0 mask 0.0.0.0.
If it's the only one set up, it will function exactly like a default gateway.

amp2030

surfthegecko wrote: »

thanks blackninja....much appreciated.

so if I set the int vlan 1 to: ip address 172.16.16.1 255.255.0.0
would the switches ip default-gateway just be on the same subnet eg 172.16.16.100 255.255.0.0

or is this not linked to the vlan interface.

The vlan ip has to be in the same subnet as the router (which you set as default-gateway) or it will not be able to communicate with it. Note that it does not impact the hosts connecting to ports that are in the same VLAN. It affects strictly your switch (so you can telnet into it, ping it, etc).

tndfr

default gateway in your switch has to be the same subnet as your gateway (i.e. router). just think of your switch like any other PC in your network, if you need to go out of your LAN than you need the default gateway to route you to other LAN segments.

if you have (a simple internetwork) just one LAN segment and the other segment is the internet separated by a router then you really dont need to set the default
gateway.

surfthegecko

so just for completeness sake would the following be the correct setup.

RouterA:
int vlan1: 172.16.16.1 255.255.0.0

SwitchA:
ip default-gateway: 172.16.16.1 255.255.0.0
int vlan1: 172.16.16.2 255.255.0.0

Then the fast ethernet between RouterA & SwitchA would be set to what?

Thanks so far guys, the picture is slowly being painted.

amp2030

surfthegecko wrote: »

so just for completeness sake would the following be the correct setup.

RouterA:
int vlan1: 172.16.16.1 255.255.0.0

SwitchA:
ip default-gateway: 172.16.16.1 255.255.0.0
int vlan1: 172.16.16.2 255.255.0.0

Then the fast ethernet between RouterA & SwitchA would be set to what?

Thanks so far guys, the picture is slowly being painted.

No.

Your switch setup is correct, but the "fast ethernet" between RouterA and SwitchA has to be set to 172.16.16.1 255.255.0.0, not "vlan1".

What routers do is direct data traffic between the different subnets that their interfaces connect to. In this simple case, one interface will be on the local subnet (172.16.0.0/16) and one, presumably, will get an ip from the ISP.

surfthegecko

Excellent...thanks for the info. I was being a bit slow and configuring the wrong aspect.

What should you typically set the int vlan1 ip address to. Would it be something else on that particular subnet or do you pick a completely different subnet all together?

I have just mapped out the following scenario:
3 pc's connecting to Switch1 which connects to Router1
Router1 then connects to Switch2 which connects 3 additional hosts.

I have managed to get them all pinging each other which has helped to clarify my questions on this post after the knowledge given by you all.

Thanks for everything guys/gals, once again Techexams forum saves the day

drew2000

surfthegecko wrote: »

What should you typically set the int vlan1 ip address to. Would it be something else on that particular subnet or do you pick a completely different subnet all together?

Typically you would give the VLAN an IP on that same subnet. What number you give it depends on how your organization allocates IP's. For example, routers could be .1-.5, with switches being .10-.20, printers could be .21-.40, and workstations .50-?.

Drew

surfthegecko

Thanks Drew....Does it not matter which subnet its on?

int fa 0/0 is on 192.168.1.1 255.255.255.0
&
int fa 0/1 is on 192.168.2.1 255.255.255.0

which one of the 2 subnets do I setup the vlan on, or does it really not make a difference?
I tried it on a new subnet of 192.168.3.1 255.255.255.0 and this didnt work.

drew2000

Surf,
Your int fa's are on different subnets - I'm losing my grasp on what your objective is.

I would start out with ONE subnet, with the router and the VLAN both in the same subnet, like this:

Router IP address: 192.168.1.1 /24

Switch int vlan 1: ip address 192.168.1.10 /24
Switch ip default gateway: 192.168.1.1/24

PC's: 192.168.1.20 - 254 /24

If you set it up like this, everything should work from a subnet perspective. I know you have multiple switches involved, now those can be on another subnet, with another router interface. Of course, unless you setup a static route or routing protocol it won't work.

There is a whole additional topic here that I am not addressing because I don't want to muddy the waters, but if you really want to get crazy you can look up layer 3 switches.

Drew

surfthegecko

Hi Drew,

I already have the int vlan1 on switch1 & switch2 configured to their subnet range as you described below, but I am now trying to configure the int vlan1 on the router so that it can be remotely managed.

I can telnet into each of the switches int vlan1 addresses to manage them but dont know how to setup RouterA's int vlan1

RouterA
int fa 0/0 192.168.1.1 /24 - SwitchA
int fa 0/1 192.168.2.1 /24 - SwitchB
int vlan1 = ?

SwitchA
int vlan1 192.168.1.100 /24

SwitchB
int vlan1 192.168.2.100 /24

Hope this makes more sense.
If im not describing it properly then apologies for this, and maybe dont worry for now, I was just trying to set it up for completeness, its not essential.

Thanks

amp2030

surfthegecko wrote: »

I already have the int vlan1 on switch1 & switch2 configured to their subnet range as you described below, but I am now trying to configure the int vlan1 on the router so that it can be remotely managed.

You don't need to set up a vlan on your router to manage it remotely. You can access it by telnet/ssh to any of its interface IP addresses (in your case 192.168.1.1 or 192.168.2.1).

drew2000

amp2030 wrote: »

You don't need to set up a vlan on your router to manage it remotely. You can access it by telnet/ssh to any of its interface IP addresses (in your case 192.168.1.1 or 192.168.2.1).

Yep x 2 . I'm not even sure that you COULD have a VLAN on a router. I'm sure on some of the high end wicked expensive models you could, but on a common router I don't know why you would need one.

All you should need to do on the router is setup ethernet 0 (and ethernet 1 if applicable) to an IP on the same subnet as your switch. Then you should be able to telnet from a PC on that same subnet that is connected to a VLAN in that subnet. Should be fine unless there is a previous configuration problem preventing it from working!

If you are still having trouble, post your config and we'll have a look!

Drew

surfthegecko

Thanks guys, I never really thought of that.
Works perfectly on both interfaces.

I think the reason why I thought it was best to configure int vlan1 was because it actually allowed me to, so thought there must be a specific reason for doing so.

All working perfectly now.

Thanks to everybody for their help.