I'm trying to go through an online course to study for my CCENT and CCNA certification exams, and I've come across a trouble spot.
In the module, he's going over basic network setup, including setting up interfaces, assigning ip addresses, the works.
At the end of the video for that portion, he's testing the connection by pinging a second machine from across the router, and having no issue in doing so, however I can't seem to make it work. Crude ASCII topology drawing below.
Currently, I can ping both ends of the router from either machine, and can ping both machines from the router no problem. What am I missing, or what have I not done in order to be able to ping one machine to the other? I want to make sure I have this working before I move on in the course.
10.0.0.0/25 10.0.0.128/25
|CPU 1|-------G0/0--|R1|--G0/1----------|CPU 2|
R1: G0/0: 10.0.0.1/25
G0/1: 10.0.0.129/25
CPU 1:10.0.0.10/25
default gateway: 10.0.0.1
CPU 2:10.0.0.130/25
default gateway: 10.0.0.129
Are the PCs in question "physical" machines? One common cause for PC to PC ping failure on "Physical" machines is the windows firewall. It would need to be disabled on the remote machine you wish to ping in order to get a response.
Thank you
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I am looking for a basic thing yet I have not found not even a single good documentation on getting it done.
I want to allocate a floating IP, then associate it to a network interface of a droplet other than eth0.
The reason is I want to have the ability to very easily switch from one IP to the other with a programming language.
In a few words, I want to be able to do these two commands and both should provide a different response.
curl --interface eth0 https://icanhazip.com
curl --interface eth1 https://icanhazip.com
Also, I want to know what to do once I release the Floating IP, how do I roll back to the starting point.
All documentation I read, rely heavily on "ip route" and "route", most did not even work, some worked but replaced completely the old IP by the floating and that's not what I want, and also they did not show how to rollback the introduced configuration changes.
Please help, I spent 1 whole day now trying to get this to work for a project, and no results so far.
I guess there is no need to know DigitalOcean, how to make this work on other Cloud Providers would apply here too I think.
Update
After asking this on DigitalOcean community forum (https://www.digitalocean.com/community/questions/clear-guide-on-outbound-network-through-floating-ip), they claim that is not supported, although there may be some solutions to this if somebody can provide such a "hacky" solution I would take it too. Thanks
In the cloud (AWS. GCP etc.) ARP is emulated by the virtual network layer, meaning that only IPs assigned to VMs by the cloud platform can be resolved. Most of the L2 failover protocols do break for that reason. Even if ARP worked,the IP allocation process for these IPs (often called “floating IPs”) would not integrate with the virtual network in a standard way, so your OS can't just "grab" the IP using ARP and route the packets to itself.
I have not personally done this on Digital Ocean, but I assume that you can call the cloud's proprietary API to do this functionality if you would like to go this route.
See this link on GCP about floating IPs and their implementation. Hope this is helpful.
Here's an idea that needs to be tested:
Let's say you have Node1(10.1.1.1/24) and Node2(10.1.1.2/24)
Create a loopback interface on both VMs and set the same IP address for both like (10.2.1.1/32)
Start a heartbeat send/receive between them
When NodeA starts it automatically makes an API call to create a route for 10.2.1.1/32 and points to itself with preference 2
When NodeB starts it automatically makes an API call to create a route for 10.2.1.1/32 and points to itself with preference 1
The nodes could monitor each other to withdraw the static routes if the other fails. Ideally you would need a 3rd node to reach quorum and prevent split brain scenarios, but you get the idea right?
This may seem a naive question, since the computer networks knowledge from university days has almost vanished throughout the years, but before getting my hands on a book relevant on this topic, I would like to find out what more experienced folks out there know about this.
Basically I would like to be able to connect a client (C) to a remote server (S), sitting in separate LANs, without adding special rules (e.g. port forwarding) to any of the routers in between.
I know that some applications (TeamViewer) use broker servers for connecting a client to a remote machine, but what I don't know is if the whole traffic between them goes through the broker server.
For my use case, I would use such a server only for initial discovery of the peers (more exactly the discovery of S by C), then the traffic would go through a connection directly initiated by C towards S.
Would such an approach be possible?
Thank you!
Unfortunately if the devices reside in networks separated by the Internet your first hurdle concerns RFC1918. In order to connect to a private IP you will have to use some level of NAT. To over come this is to build a VPN connection between the two networks affectively connecting as if each are local to the other. Please note that to avoid any NAT configuration in this scenario requires that the private networks are using different subnets IPs
A bit of a weird situation that I haven't come across. Note: it's not really a problem and I'm just really asking this out of interest.
My friend switched to a new ISP (same ISP as me, he lives one city over) and they just installed the new router today. He asked for my IP to join my teamspeak server which is temporarily being hosted on my local machine. He's joined it before many times without issue. He said it's not working today.
I told him to ping me, no response. I pinged him, also no response. At this point I was confused since I had never come across this situation before (maybe it's common, I'm no networking expert though). I ran a tracert and told him to do the same, mine reached a domain which was prefixed with his city name and his reached a domain prefixed with my city name, both timed out before actually reaching the destination IP.
At this point we decided to just use Discord instead and assumed this problem would resolve itself, I tried one last thing. I ssh'd into my work development server located in London and did a trace to both IPs. My IP traced fine and his IP timed out.
All I can think of is that routing tables for his new router aren't properly set up yet, my knowledge on networking doesn't really extend beyond this! I'm really just interested in what's going on here and would love an answer from a networking expert!
ICMP protocol might be disabled or blocked at any hop along the way, which would disrupt tracert.
Given that you tried pinging from two different endpoints to his PC could indicate that the ICMP blocking is happening somewhere closer to his endpoint.
With regards to the teamspeak connection, his new router might not be configured to allow the appropriate ports through. All home routers have different ways of configuring port-forwarding, but I'd check documentation there.
So, I recently installed synergy because I was tired of using two mice and keyboards. Problem is, set up is not working. First, the setup.
Server:
Desktop
Windows 7 64 - on our home network, part of Workgroup: WORKGROUP
Client:
work issued laptop
Windows XP SP2 32 - on home network, part of workd Domain: DOMAIN
Server is set up, all the computer names are correct. I'm a bit of a noob at networking things, and I don't want to mess up the configuration of my work laptop again (I already switched the domain to my workgroup, BAD). So, any suggestions that aren't too crazy please, since it's a company laptop.
I've tried putting in the ip on the client as well, firewall is allowing on the port in use, just can't get it to work. I think I'm SOL with the Workgroup/Domain difference though...
From what I remember, Synergy doesn't care about the workgroup and/or domain, it just needs to be able to communicate with the server/client IPs. Did you try to manually insert IPs of client/server?
In a very similar situation I discovered that when trying to ping my non-domain desktop with its workgroup name the dns resolver was appending the work domain to the desktops name. So when I tried synergy with an IP address I successfully connected the two computers.
The only caveat I can offer is maybe you needed to add the application to the windows firewall exception list for both machines. I would assume the port setting was the same between the two computers (default is 24800) in which case you should only use the IP address because the application knows to access 24800 via that setting in the advanced configuration.
You can add the program to the whitelist or specifically the port if you prefer via the Windows Firewall. On a side note - I am also using an older version of synergy (1.3.1) and not the latest as of this answer (1.4.2 Beta) which did not work for me, but I will assume it's because my server was running 1.3.1.
I chose not to update all 6 machines and their respective horrific configuration constructs that synergy loves to enforce upon us. [caution... rant: x is left of y and y is right of x... really? are you sure about that Einstein? Synergy could at least INFER that bit of logic instead of REQUIRING it!]
Hope that helps.
Our software includes a module to stream live video data to multiple clients. Most of time it works fine, but in some cases it seems to have caused some malfunction of windows network.
When it happens, the LAN connection status in network connections still says "connected", and the IP address is normal. But I cannot ping any other device in the network. The only way to fix it is to disable and then re-enable the network connection.
This problem seems to be OS-independent, it has happened on XP, Vista and Win7 machines.
Has anyone experienced anything similar? Did my application crashed the network stack? or is it something else?
More likely a fault with the networking switch unless you have a really bad NIC.
Cheapest route is to first replace the NIC, but ideally you should be able to reproduce the fault in a test harness so try with a direct crossover cable between two hosts first to rule out the networking infrastructure being at fault.
∴ Server Fault could be a better place to ask the question.