Month: December 2017

How to netboot OpenBSD installation

I have tried to configure a network boot environment for FreeBSD some years ago. Well, my trying stopped immediately after reading the documentation for this. If I remember correctly it requires a bunch of files on a TFTP server, a NFS share as root file system and settings in the DHCP server. While TFTP and…


How to auto mount iSCSI LUNs on OpenBSD

I use iSCSI LUNs to increase the available disk space on one of my apu2 boxes at home. After patching iscsid(8) so it can connect to my Synology I’ve mounted the LUNs manually. For testing this is fine. Soon I have realized that the LUNs are going to be a permanent solution. Therefore, I have…


Patch for cu(1) to config escape character

As a sysadmin I often use tools to access terminals on other systems. Most of the time this is ssh(1), sometimes it is telnet(1). Both have the command line flag -e. Using this flag I can change the default escape character ~ (a tilde) to something else. There is one tool in the base system…


How to build redundant DHCP servers on OpenBSD

For years, sysadmins like me were told that you could not run more than one DHCP server in a broadcast domain. Then the IETF created a draft for a failover protocol between two DHCP servers. ISC implemented this draft in the DHCP reference server. With Windows Server 2012 Microsoft implemented the same draft into their…


Patch for iscsid(8) to access Linux targets

  The iSCSI protocol, originally described in RFC 3720, which is now obsoleted by RFC 7143. This no big deal, because the newer RFC is a consolidation of the various RFCs about iSCSI. There is a standard, and both OpenBSD and Linux claim to base their implementations on RFC 3720. What could go wrong? My…


How to resize partitions on OpenBSD

My home mail server complains about a full /var partition. Actually, the partition is not full. However, it does not have enough free space to update the malware database of ClamAV. Therefore, I have to do something about it. Unfortunately I do not have any free space adjacent to /var on the disk. So growfs(8)…