Since server-side ascp processes are spawned by sshd, you need to enable core dumps explicitly and set up a special directory where the core dump files will be stored. Use the following instructions to do this.
1. Edit /etc/security/limits.conf.
Add this line at the end:
* soft core 400000000
This will enable core file up to 400MB (approximately)
Also make sure that /etc/profile doesn't contain something like ulimit -c 0 which would turn core files off.
2. Set up the directory where core files will be located
To store your cores in /tmp for example, issue the following command:
echo "/tmp/%e-pid%p-uid%u.core" > /proc/sys/kernel/core_pattern
If you choose another directory make sure all users have permissions to write there:
chmod 777 my_directory
3. Test the new system
To test, start an ascp transfer to this server from a client machine.
On the server, determine the PID of the server (in my example: 7777), and kill it by running the following
# ps aux | grep ascp
# kill -SIGSEGV 7777
Then, you should see the core file at the top of the list after running the following:
ls -lt /tmp