Change pptpd port on CentOS
I was testing Point-to-Point Tunneling today, between a CentOS 6 server running pptpd
, and some Mikrotik routers as
the clients, and I wanted to change the listening port on the pptpd
side. After searching and reading a bit of
documentation for a while, I was surprised to find that pptpd
respects the record for pptp
as defined in
/etc/services
.
LPIC-2 Revision
My list of topics to revise, before taking the LPIC-2 exam. Note that this list was compiled before the exam objectives' revision in October 2013.
DHCP
- Example Servers: bigpie1, sds1, nicds1, officesrv
- CentOS Install DHCP
- dhcpd.conf
LDAP
- Example Servers: ldap-master, ldap-slave
- Locate and examine LDIF files
- ldapadd, slappasswd, ldappasswd, ldapdelete, getent, ldapsearch
Routing
- /proc/sys/net/ipv4/ip_forward and sysctl.conf equivalent
- RIP with routed
iptables
- iptables chains, default policies
- flush tables, add rules
- configure NAT
SSH * Support programs: rpc.idmapd, rpc.mount.d, rpc.nfsd, rpc.statd, portmap * Setting up exports with NFS in /etc/exports, and on the fly with exportfs * showmount, nfsstat, rpcinfo * Mount over NFS
FTP * PAM Basics, PAM Stacks, Examples of PAM Modules * PAM Configuration, NSS Configuration
TCP Wrappers
- /etc/hosts.allow, /etc/hosts.deny
- Calling TCP Wrappers from /etc/inetd
- /etc/xinetd
Snort
- Network Design for SNORT
Fail2Ban
- Fail2Ban configuration
Bootloaders
- Identifying active bootloader on a system (based on files on disk or with bootinfoscript)
- LILO Error Messages
- GRUB Legacy Error Messages
- GRUB2 Error Messages and Rescue Console
Boot Time Troubleshooting
- initrd
- dmesg
- /etc/inittab, runlevel, SysV and Upstart
Hardware Troubleshooting
- Hardware detection (/proc/cpuinfo, lspci, lsusb, lsdev, lsmod)
Log files Troubleshooting
- Helpful files: syslog, messages, dmesg or boot.log, secure, cron, lastlog
- Scanning Log Files with head, tail, less, grep, logcheck
- syslogd configuration
- Logrotate configuration
Software Troubleshooting
- strace and ltrace, ldd, lsof, strings
- Library Dependencies
- Kernel options in /proc/, sysctl, /etc/sysctl.conf
- init and the process tree
- top
Troubleshooting Login and Accounts
- Logins with login, XDM, KDM, GDM, getty
- Network Logins with Telnet, SSH, X, XDMCP, VNC
- Users management with usermod
- Login variables in /etc/login.defs, /etc/profile, /etc/bashrc, ~/.profile, ~/.bashrc
Cron
- Schedule Jobs with Cron
Linux Professional Institute Certification 2 (LPIC-2)
LPI changed the objectives of LPIC-2, with the new ones available from November 1st, 2013, see: LPI revises objectives for LPIC-2 and LPIC-3 Linux certification programs.
Links
dracut
Copying from the man page:
dracut creates an initial image used by the kernel for preloading the block device modules (such as IDE, SCSI or RAID) which are needed to access the root filesystem.
dracut reads configuration files in /usr/lib/modprobe.d/
and in /etc/modprobe.d/
by default, unless run in
generic mode, in which case it ignores host-specific configuration in /etc/modprobe.d/
.
Again, copying from the man page:
-H, --hostonly
Host-Only mode: Install only what is needed for booting the local
host instead of a generic host.
The default configuration is host-only. This is defined in /etc/dracut.conf
, in the line:
hostonly="yes"