Archive
Posts from 2006
Logfile format for BIND queries
While perusing my BIND query logs, I came across the following entry: All of the text up to the record type (MX in this case) made sense, but I had no idea what the "-E" meant. Being the curious person I am, I dug through the BIND source code to locate the logging code. After a couple of find statements, I was able to locate the logging code in query.c: So a "+" or "-" in a query log entry indicates that a client requested recursion, and the "E" means that the query requested EDNS0. I would like to thank Knobee for his feedback on this post.
$ read more →Using mdb to locate the value of a symbol
I recently needed to locate the value of a specific symbol in the .data segment of an ELF executable. Prior to learning that mdb and gdb could be used to perform this lookup, I typically did the following: Use nm to locate the symbol and it's offset from .data Use readelf or elfdump to locate the address of .data Run hexdump on the library or executable that I wanted to lookup a value in, and check for a value at the address of step 1 + step 2 This seemed tedious, so I asked around to see if there was an easier way. It turns out I was overcomplicating this, as mdb and gdb can be used to resolve the symbol for me. Here is how to use mdb to display the value of the symbol mod_log_forensic in the library mod_log_forensic.so: It's all about simplifying your IT life…
$ read more →Solaris 802.1Q interface format
While reviewing some notes last night, I came across an entry in my notebook that described how to configure Solaris interfaces to support 802.1Q tagged queing. Given a physical interface named "ce0" that will be associated with VLAN 500, the formula to create the interface would be: So in the example above, you would use an interface named ce500000 to tell the host to process 802.1Q tagged Ethernet frames destined for VLAN 500. I am still not sure why Sun chose to use this format, since you can't just look at a name and know what it is. Luckily this annoyance will be fixed when the clearview project integrates into Solaris (clearview will allow you to use vanity names with interfaces).
$ read more →Bash short cuts / hotkeys
I use bash as my primary shell, and have come to rely on the following bash short cuts:
$ read more →Cron format
I've been cleaning out a bunch of super old notes this week, and am going to post them on my blog for future reference. In case I incur a head injury and need to memorize the crontab format again, here it is as ascii art: You will probably see a few of these posts hit my blog in the days to come.
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