It can be used as the source address, and in fact it is the source address when you pinged localhost!
Network traffic to/from localhost is the same as any other network traffic except that it never leaves the host. The localhost address is both source and destination address.
There are two main ways this can be done, the choice of which is largely made by your ISP.
The set of ip's your isp has given you (typically a .. subnet) can be routed through another IP. This configuration mostly applies to business where I'm from. In that case the router has an internet-facing public ip, and a seperate also public "lan"-facing (...
You need to connect your home network and office network via a VPN. Then your home network router would send traffic to 10.0.1.0/24 via office VPN server and office network router would send traffic to 10.0.0.0/24 via home VPN server.
Adding further locations / components is possible, you need to have similar router's with VPN tunnels set up and routing ...
21:49:09.405200 IP client.55574 >
server.tftp: 22 RRQ "pxelinux.0" netascii
21:50:29.823916 IP client.1038 > server.tftp: 40 RRQ
"pxelinux.0" octet tsize 0 blksize 1468
The TFTP transfer of PXE components i.e. NBPs like pxelinux.0 should always be type octet and not netascii
From your post it looks the first ...
There are many places where a network packet (e.g. TCP/IP packet) can get inspected on a Linux system. When you mention TRACE, I'll assume you mean the TRACE from iptables. tcpdump and iptables look at packets at different times during the packet's flow through the system. So as Michael Hampton commented, "One is before NAT and one is after NAT"....
Try checking with tc:
# tc -s qdisc show dev tun0
qdisc mq 0: root
Sent 889257959003266 bytes 478800964 pkt (dropped 162977296, overlimits 0 requeues 1784154649)
backlog 0b 0p requeues 1784154649
The important part is backlog 0b 0p which tells you how filled the TX queue is in packets and bytes.
Tc gets this information from kernel using netlink ...
The tunneling traffic from the problematic side was coming in as the tunnel ip when viewed in tcpdump on the ec2. Turns out the pfsense had Hybrid Outbound rule generation turned on in NAT and not the default Automatic Outbound.
I found these very helpful tools:
Cisco packet Tracer: It's a network simulation tool built by Cisco, And there's a course called Introduction to Packet Tracer to guide you on how to use it
Wireshark: It's a network protocol analyzer. It lets you see what’s happening on your network
Since you say that you cannot see the labeling on the jacket, and you almost certainly do not want to spend hundreds to thousands of dollars on specialized testing tools, the simplest thing to do is to try it and see. Get two computers, hook one at each end, see if they negotiate a gigabit connection between them. Then use iPerf (or similar tools) to send ...
Cat5 vs Cat5e is a specification of cable quality, not a different kind of cable or a different kind of jack. It should be written on the insulation periodically along it's length. I found a picture of an example: https://www.lanshack.com/Assets/Cat5e_stock.jpg
Every network interface of every KVM guest is presented by the tun/tap interface in the host system. To attach the KVM guest to the bridge use this command: ip link set master virbr0 dev <tun-iface-name> for the corresponded tunnel interface.
First, let me understand what you mean by Connection failure from the technical point of view?
When a user tries to access a website and get an error, usually this error would be (1) a DNS error (couldn't resolve domain name) or (2) any kind of access error like "Internal Server Error - HTTP/50x", "Bad request - HTTP/400", "Request ...
The router OS tries to keep CPU load as low as possible. Therefore even when interface processor modules do not have their own ASICs they utilize separate packet processing CPU loops/threads.
When ACLs filter out uninteresting packets they just skipped silently, freeing packet queues memory and not affecting CPU.
In fact packet processing of a single 64K ...
Looking at your scenario, I assume the following:
Traffic from 0.0.0.0/0 destined to X.X.X.X on port 443 must be forwarded to VM1 in VLAN-1
Traffic from 0.0.0.0/0 destined to X.X.X.X on port 5432 must be forwarded to VM2 in VLAN-1
Traffic from 0.0.0./0 destined to Y.Y.Y.Y on port 443 must be forwarded to VM3 in VLAN-2
If my assumption is correct, I would ...
WoL uses a specially crafted pattern somewhere in a network frame. A packet may be routed but not without special preparations.
Most tools send a limited broadcast (to 255.255.255.255). L2 broadcasting (to ff-ff-ff-ff-ff-ff) won't work across a router generally.
You could use a directed broadcast (e.g. 192.168.0.255 for the 126.96.36.199/24 subnet) but the ...
You've gotten the gist of it right. It's basically a case of replacing 255.255.255.0 with 255.255.254.0 everywhere.
However, you'll need to make sure that the neighbouring /24 is actually free. For example, say that you're currently using 192.168.1.0/24. Changing that network to 192.168.1.0/23 means that you're now also using 192.168.2.0/24, as 192.168.1.0/...
In case you are using systemd-resolved instead of NetworkManager, add the following line to
the very beginning to /etc/resolv.conf.head:
Prevent NetworkManager from modifying /etc/resolv.conf and leave everything to
systemd-resolved by adding the following line under the [main] section of
I was looking for the answer to the wrong problem.
I had deliberately imported this VM using virt-install with option '--graphics none'. I had expected it to come up immediately without any further action. I was mistaken.
As occurred here: How do I connect to my libvirt/qemu/guests ? (with no ip address), once I imported a new VM with '--graphics default', I ...
I would like to use the regular Ethernet adapter instead of vEthernet.
Is the correct procedure to check all the items on Ethernet that are
currently checked on vEthernet. Then, uncheck those options on
No. What you're seeing is because your management OS (the Hyper-V host) is sharing the physical network card with the virtual switch. The network ...
We have two type Configuration IP , Static and auto (DHCP) your DHCP server must be capable to assign IPV6 to your client
for configured Manuel based on other app like setting in apache virtual host you need write script and set in Manuel in setting like configuration file per interface in
/etc/network/interfaces.d/ directory instead of /etc/network/...
This has, of course nothing to do with a business IT environment. A couple of tips, though:
Don't use ".local" domains in real life. They cause more trouble than they're worth. The yearly cost of a domain name is not high and will open up more opportunities to learn as a hobbyist.
To solve your problem you don't necessarily need to switch operating ...
And it was the complete opposite of what I was expecting the solution to be.
The problem was not on my origin server's end, all the permissions and firewall rules were all set up correctly - this was an issue on Cloudflare's end.
Because I had configured the site to use https only, attempting to access the site via HTTP returned 403 forbidden because ...
The default route of the one active interface is used.
I guess your phone has 2 sim slots
usually an inactive interface unless your VPN is up.
"2:0:0:0:0:0" is a HOST over the "enc" interface, tunnel or vpn
The interesting parts are "2409:8800:" a tunnel to somewhere in "China Telecom", hopefully inactive.
Configuring the servers to connect to multiple firewalls is unusual.
A more typical configuration would be to put a load balancer between the firewalls and the servers, or configure the firewalls for high availability.
Every queue discipline must have unique handle. Also, the graph of queue disciplines and classes should be non-cyclic: every node should have only one parent. So, there isn't way to achieve what you want.
There are hard limits against API request rate in GCP and they are counted by the project (regardless of service account used).
The only methods that are exempt from the count are *.get and *.list.
API rate limits define the number of requests that can be made to the
Compute Engine API. API rate limits apply on a per-project basis. Rate
limits are enforced ...
1/ no, vm to vm bridged communications remains inside the host.
2/ I think you should consider using macvlan VEPA mode instead of bridged mode if you want your switch to be able to apply acls. [more details here https://hicu.be/bridge-vs-macvlan]
Small websites use a single server or several ones with a load balancer in front of them, but big ones (like Google or Microsoft or Facebook) will use a mix of several techniques to increase availability and to serve your request from the nearest geographical location.
What this means in practice is, when you query DNS for those sites, you can get all kind ...
For this specific point of time when you made the DNS query, yes, 188.8.131.52 is the IP address where your broser will connect when you go to google.com. It doesn't matter if it is a load balancer or real web server, it is still the address you need to allow.
However, in general, allowing only specific IP addresses doesn't work with the general internet.
RFC 2233 adopted expanded 64-bit counters for high capacity interfaces in which 32-bit counters do not provide enough capacity and wrap too fast.
You are really asking two questions - I'm going to focus on the less common
I assume there are more users then the ones who are allowed to login but these other users are given accounts for non-ssh use. There are more than one way to skin that cat - but this is what I like to do:
Create a new group login (sudo groupadd login).
Add your ...
Not that long ago, typical designs forced all traffic through one big firewall as a security control. That is an advantage: by being at the Internet gateway, the network team can enforce a security control even if they don't manage every device. By necessity, such a firewall needed to be big with expensive custom hardware.
Now, it is possible to categorize ...
If you have a router/firewall and you are doing 'router on a stick' or have each subnet connected from the router via its own interface to the switch capable of Layer 3 also, then on the switch you can have multiple gateways of last resort.
Lets take a router with 2 x LAN Subnets of 10.0.1.0/24 and 10.0.2.0/24
Router LAN Interface is setup with:
Fa0/0.1 = 10....
Welcome to Server Fault.
You are looking for a reverse proxy.
@Gerald Schneider made an excellent tutorial about setting up a reverse proxy with nginx or Apache, but if you want to do it with IIS (which is not a great idea since IIS is really slow for those things), you can have a look here.
EDIT: after reading what you exactly wanted (I completely messed up,...
As far as I am concerned its a matter of belt and braces. A hardware firewall helps to keep the bad guys out of your network. UFW and the like help you keep the bad guys out of your server if they do get onto your network. Generally routers are routers first and foremost and firewalls a distant second. They are better than nothing, but not a substitute ...
Consider a load balancer. This service distributes connections to backend servers. Typically implemented with a reverse proxy. Connection routing rules are whatever you wish, often based on HTTP Host headers or backend health.
Will DNS return to me a public address of the router/lan where servers sits? As far as know this is the only address that dns can ...
Will DNS return to me a public address of the router/lan where servers sits?
The DNS will return WHAT IT IS TOLD TO RETURN. Main problem is - do you have a STATIC IP? Or not? Anyhow, yes, it should end there.
As far as know this is the only address that dns can know.
No, DNS can know any address that is put into it. This is the only one that makes sense - ...
You can get around this with port forwarding. Forward port 80 > 80 on one of the servers and 81 > 80 on the other.
Then from outside you can do www.domain1.com to get to the first server and www.domain2.com:81 to get to the other.
Another alternative would be to run both sites on the same server and let the web server itself sort out which pages to ...
You haven't specified a route to reach the 10.51.23.whatever network, so such traffic is passed to the default gateway. You need to specify a route which tells the machine how to route that traffic.
# ip r add 10.51.23.0/24 via 10.51.85.191
Note that this only gets you one way traffic. The other end must also know how to send traffic back to ...
This is possible with iptables NAT masquerading.
Use two linux machines, on subnet 184.108.40.206/24.
ips .10 to .49 routed through 220.127.116.11 (use iptables and nat table masquerade)
ips .51 to .89 routed through 18.104.22.168 (use iptables and nat table masquerade)
If you are using dnsmasq, DO NOT activate DHCP.
I managed to solve the issue my clearing my iptables firewall rules. This is the command which helped me.
sudo /usr/sbin/iptables -F
This command will flush all the current rules. With the sudo /usr/sbin/iptables -L -v it shows all the current rules in the VM. From the view I could view that one of the rules is set to REJECT.