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Gurgle
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Routing Between Two ports CRS112-8G-4S-IN

Sun Aug 08, 2021 5:57 pm

Hi All,
Bought the above yesterday, no experience on MikroTik but did previously buy the correct serial lead to login to an old Cisco switch, which ironically don't work on the 112.

I need to route between two subnets (like 192.168.1.0 and 192.168.99.0 ) the 112 being the single device between the two subnets.
I don't really do command line or Linux but happy to work from console if this helps and can connect to the console.
I have tried the web interface and quite happy with that, assumed the Windows interface is similar.
I didn't succeed with the console connection (as above using USB to RJ-5 lead for Cisco) (I did see a page on serial connects. From printer/plotter connecting years ago + modems I'm familiar with the vagaries of serial connections wiring and functions but I don't want to cut up the Cisco cable, so could make one if needed and unlike the Cisco one hopefully it does not need a chip, i.e. just wires.
I am reasonably happy with IP terminology address, masks. default gateway, subnets CIDR etc. mainly IPv4 though and Windows routing table, adding static routes etc.
I know what a Level-2 (switch via MAC address) and Level-3 (IP address routing) devices are.
I'm not familiar with the terms bridge etc. in the MikroTik context, plus why there are ref to cpu (possibly in a list of ports)
Basically understand VLANs etc.

Essentially all I need is two ports (can I use any?) one for subnet A one for subnet B and for these two to communicate.
I assume I have to configure address on two ports one for each subnet
The default gateway for Internet access by the 112 needs to be direct to one specific subnet (say A) so that traffic only goes that way (ok I know default gateway means just that, but static routes mean you can use a gateway out to a different subnet for some traffic.
Both subnets will by other means have Internet access i.e. both have an Internet router.
Eventually a PC (or two) on subnet A needs to be the only device that can access B via the 112. but
for testing purposes and getting the connection between subnets going everything on one subnet can see the other

I'm more than happy with minimal config to do the job, but interested in exactly what needs configuring or NOT.
For example I assume I just need the two ports configured with appropriate IP for its specific subnet
Do I need to specify/configure a specific protocol in the router section like OSPF ?
Do I need to configure VLAN(s)
Is NAT involved (as in home router to Internet)
I don't need DHCP for either subnet
Is a staic route in each direction possibly all I need?
Finally only specific PCs on one subnet are allowed access on the other (could the need for DNS etc. affect what is allowed through?)

I have single subnet at home (10.0.4.0) with all my devices on it. I have set the 112 to a static address on this network and connected it to port-2. My Laptop is connected to port-8 initially on 192.168.88.x to connect, then on a 10. address. This does not quite mirror the eventual use where I assume I configure two different ports with suitable subnet A and B addresses, but I assume I can configure two free ports then move my network connections to one and laptop to the other to continue the testing.

Enough for now as I could be barking up the wrong tree.
 
Gurgle
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Re: Routing Between Two ports CRS112-8G-4S-IN

Tue Aug 10, 2021 7:19 pm

Update...

Requirement, not an Internet router function, just to use the CRS112-8G-4S-IN as a router, a Level-3 device.

I want to have two subnets A and B connected to two different ports and be able to route traffic between the two. Initially all traffic.

I have sorted working at the command like using my Cisco USB to RJ-45 cable, I had the baud rate wrong (Doh!) works great using Putty, just look in W10 device mangler to see which Com port it emulated.

I have a single router, not two as in the example shown here...

https://wiki.mikrotik.com/wiki/Manual:S ... ic_Routing

To an absolute beginner with MikroTik this simple example is a godsend, I could see which prompt to be at and how to setup IP addresses on ports etc. Disadvantage is that this example uses two routers, the sort of thing you would find when they are a distance apart, say between two buildings.

My situation is using a single router linking two networks, i.e. two different subnets, on two ports of the router and I suspect that this requires a slightly different possibly more detailed config than the above.

I setup address for my home network on one port and a different network address on another port, worked fine and can both be pinged from the console prompt.

I then used the add dst-address=10.0.4.0/24 gateway=192.168.99.1 command and one in the opposite direction to say to each port the opposite one is its gateway, hoping that this would route traffic between the two ports

This didn't work, possibly this page is the right approach?

https://wiki.mikrotik.com/wiki/Manual:V ... Forwarding

bfn..
 
biomesh
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Posts: 561
Joined: Fri Feb 10, 2012 8:25 pm

Re: Routing Between Two ports CRS112-8G-4S-IN

Tue Aug 10, 2021 8:40 pm

This is really a switch and won't route very well due to the very weak CPU (400MHz mips). I would suggest following the wiki examples for VLANs and sending those two vlans to your router and let it handle the routing for you.

https://wiki.mikrotik.com/wiki/Manual:C ... s_examples

If the router is a mikrotik device, you can use one port on the crs112 as a trunk port and on the uplink port (or bridge) on the router create two vlan interfaces. One for each network (the vlans should match what is created on the crs112 switch). The vlan interfaces on the router would have an ip address and that ip address would be the gateway address used by clients. You can also create dhcp server for those vlan interfaces as well.

The link above also covers routing on the switch itself, but looking at the routing performance ( https://mikrotik.com/product/CRS112-8G- ... estresults ) you most likely won't be satisfied with the results.
 
Gurgle
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Re: Routing Between Two ports CRS112-8G-4S-IN

Thu Aug 12, 2021 9:19 am

Appreciated!

I bought the CRS112-8G-4S-IN as a testbed , a way to get the MikroTik o/s to play with without spending a fortune on something that may never get used.

Now I have sorted the console connection and WinBox it is easy to see the effects of a config via the Windows interface, this is a really handy feature.

I will now be looking for a 24 port router with Gigabit ports for general use, with enough grunt to keep PCs on twelve ports happy talking to the web and a NAS.

The 8 port may still get used as the routing between ports is only for one PC to connect to a different subnet and monitor or be used for some admin work.

What is interesting is the "The Dude" network management s/w, but I guess looking at the limited spec of the 8 port it possibly wont run on that.

Any thoughts on why the VPN approach would be better than say static routes appreciated, regardless I may try this simply to get some experience on configuring.

Thanks..

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