So i have a question, my internet is connected with a modem that is set in bridge mode to a router that is connected to my computer and also gives WiFi.
The default gateway of the devices is the IP of my router, 192.168.0.1 but the default gateway of my router is 190.17.240.1 and since it's a public IP adress it means that the router sends directly the IP package to the ISP router instead of sending them to the modem gateway and then the modem send it to the ISP. Right?
No bully pls.
A router has two IP addresses, OP. Not certain what you're asking but there will be an external interface that is connected to your modem where it has the IP from your ISP (your modem just passes shit straight to the router) and the internal address for your home network. Your router's default gateway is your ISP's router. Machines on your home network's default gateway will be the internal IP of your router
Not your personal tech support.
>personal tech support
OP clearly needs help with his homework, not diagnosing an actual issue.
Oh i didn't know this, so the ISP works kinda like a local network too right? Thanks
Are you retarded? Im not trying to fix anything.
Your router has an IP packet it wishes to send to Jow Forums. It checks its routing table for the appropriate gateway and sees that it must send this packet to your ISP's router.
To accomplish this, your router looks up the ISP's router's IP in its ARP table and gets its MAC address. It then sends the packet with a layer-3 destination IP address of Jow Forums, but a layer-2 destination MAC address of your ISP's router. It transmits this packet on the wire.
Your modem, in bridge mode, receives this packet. It decodes the destination MAC address of the packet and sees that it is addressed to your ISP's router. It looks up this MAC address in its bridge table and sees the ISP's router is on the WAN port. It transmits the packet on its WAN port. It never decodes the packet on a layer 3 level and does not consider any IP addresses when deciding what to do.
Your ISP's router receives the packet, decodes the layer 2 destination MAC, and sees that the packet is addressed to itself. It unwraps the layer 3 packet wrapped inside the layer 2 packet and decodes the destination IP address, which is Jow Forums. It consults its routing table and the cycle begins again.
I bet the router would kill itself if it saw what was inside the packets it was routing
Sorry for being retarded but to make it clear, the modem does not delete the source MAC adress of package to input his own MAC adress? it just looks and sends it like that? and then when it returns the ISP sends it again to the MAC adress of the router instead of the modem's MAC ID right?
Look up CCNA. Study for it.
If you want to learn these things, get a router that supports netflow, like a Mikrotik, hook up Wireshark on your PC to it, and inspect the packets going in and out of it.
Thanks for the advice, i will dig into that, i already have Wireshark i use it to look at port 80 ACK SYN and stuff like that, recently got a 1841 too.
Routers don't have a "default gateway" however they can have a default network where they forward packets with IP's they don't recognize, which is how traffic gets out to your isp in the first place. Is this on your 1841?
>Routers don't have a "default gateway" however they can have a default network where they forward packets with IP's they don't recognize.
Oh thanks for the clarification then, no, my home router is just an stinky tp-link with a technicolour modem
Gotcha.
>70595258
>Oh i didn't know this, so the ISP works kinda like a local network too right?
The whole internet is essentially a bunch of LAN's connected with routers.
So your public IP is 190.17.240.1, which means your routers outward facing interface must have an IP that is on that same subnet, perhaps 190.17.240.2 because it's probably a /30. Your routers internal port is 192.168.0.1 which should be the default gateway of all your devices.
The router will have a default network on it to route all unknown ip's (eg some webserver that clearly isn't on your subnet, therefore your router has no idea where to send it by looking at it's own routing tables) out of a specific interface, in your case it's your outward facing interface. The ISP will know how to route that packet due to it pairing with other ISP's, and that's how your anime waifu-posting gets to Jow Forums.
>your public IP is 190.17.240.1, which means your routers outward facing interface must have an IP that is on that same subnet, perhaps 190.17.240.2
Well this is confusing because i think of 190.17.240.1 as my ISP router IP but since my router is in like a LAN from the ISP i guess in the end it is my public IP right? just like with my devices and 192.168.0.1, that's what you are trying to say or i am retarded?
>/30
>wasting half your scarce IPv4 space on network and broadcast addresses
it's probably a /24 with layer 2 port isolation and possibly a 255.255.255.255 subnet mask
>since it's a public IP adress it means that the router sends directly the IP package to the ISP router instead of sending them to the modem gateway and then the modem send it to the ISP. Right?
Yes, that's correct. That's pretty much what bridge mode means. A modem in bridge mode *basically* just converts between two different types of cable and not much else, it doesn't even have an IP address.
(That's not entirely true. But it's true enough for today's purposes.)
right
when the modem is set in bridge mode, your home router receives a public IP address for it's WAN interface and every packet leaving it will have a destination IP header with the ISP's gateway IP (190.17.240.1) in it.
pretty good
I'm saying that just like the devices that connect to your router must be on the same subnet as your internal port on your router, so too must your router be on the same subnet that is on your isp's port that faces towards you.
>/24
>255.255.255.255 subnet mask
You are retarded.
Also, you have clearly never worked for a carrier.
That's standard NAT procedures dumbass, read a fucking book