We are currently receiving a 30Mbps Spoofed UDP flood against one of our applications that is causing high CPU usage, we have a dedicated firewall running a basic version of linux with IPTables. Looking at the traffic logs, all of the spoofed UDP traffic has a header identification number of 31336. Is it poss…
Tag: networking
Detect IP-Address change on an interface
I would like to trigger a service when a change of an ip address on a specific interface occurs. Is there a target for this or some other method I am not aware of to achieve this using systemd on Linux (Kernel 3.19)? The service would be used to send a SIGNAL to a defined process. The Linux is running
Access SSH client IP address, within a screen session
Accessing the IP address of a connecting SSH client is possible via environment variables (such as SSH_CONNECTION), as described in Find the IP address of the client in an SSH session In a GNU screen session though, those environment variables are defined by whoever started the screen to begin with. Is there …
Undefined reference to `getaddrinfo_a’
I get linker error while compiling a minimal program that uses getaddrinfo_a on Linux. The program in question Compiler output: Answer You are using command in wrong way. Use -lanl should come after not before file name. https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html -l It makes a difference where in t…
The domain and search options in resolv.conf
Let’s say you have a resolv.conf file that’s something like this. Then let’s say you just changed it to this. Would these both do the same thing? Is one slightly better than the other? Why would declaring both a domain and search not be recommended? Answer The existence of both keywords are …
Prevent Docker Compose from creating separate network
I discovered that Docker Compose places containers in a separate network when using version 2 of their YAML syntax. This makes linking with existing containers difficult. Is there a way to prevent this, and revert to the behavior of version 1, without actually reverting? Answer Is there a way to prevent this,…
How to get linux interface alias(IFLA_IFALIAS) programatically for an interface?
We can set alias to an interface using the command To see that; It is set as an alias. Now I want to read this in a C program, and I am not having an idea. I did make a google search, and even tried to look into the iproute2 (provider of this cli), but to no avail. Can any
Cannot get the available bytes from the unix domain socket
I am sending N bytes from a unix domain socket (AF_UNIX, SOCK_DGRAM) to another. However, if I read X bytes from the other socket, where X < N, a subsequent call to read() blocks and I cannot get the rest of the N-X bytes. Is this an expected behaviour for unix domain sockets? Is the rest of the N-X bytes
Linux Map many internal IPs to one external IP [closed]
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack …
Iptables setup on VPN client having LAN [closed]
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack …