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Posts in Networking
Interesting NFSv3 errors
While reading through RFC 1813 (NFSv3 RFC), I came across the following interesting NFS error: NFS3ERR_JUKEBOX The server initiated the request, but was not able to complete it in a timely fashion. The client should wait and then try the request with a new RPC transaction ID. For example, this error should be returned from a server that supports hierarchical storage and receives a request to process a file that has been migrated. In this case, the server should start the immigration process and respond to client with this error…
$ read more →Debugging TCP connections with tcptrace
Debugging TCP problems can be difficult and time consuming, especially when the connection end-points lack tools to observe connection behavior. One such tool that should be on every system is tcptrace(1). This awesome utility can assist with pinpointing network issues, and can help with debugging TCP performance and reliability problems. tcptrace(1) operates on tcpdump and snoop binary files, and provides numerous statistics and connection details for each capture file passed as an argument…
$ read more →Viewing NFS client operations
While reading through the NFS RFCs this week, I decided to write nfsclientstats .pl to view NFS operations by process: The script uses the DTrace FBT provider, and produces output that is greater than 80-characters. If you are an 80-column purist, you might want to refrain from downloading the script. ;) Hope folks find this useful!
$ read more →Getting WPA working with FreeBSD
I recently purchased a Dell C400 to play with various x86 Operating Systems. After mucking around with numerous Operating Systemts (Windows XP, OpenBSD, Ubuntu, OpenSolaris, Solaris 10 GA), I decided to convert my laptop to FreeBSD 6.0. Since I like to wander around my apartment with my laptop, I needed to get 802.11 wireless networking with WPA security working. After reading through the FreeBSD ifconfig and wpa_supplicant documentation, I learned that I needed to create a wpa_supplicant configuration file…
$ read more →Viewing name service cache statistics
On the Solaris and Linux systems I support, I like to run the nscd (Name Service Cahing Daemon) daemon to cache password, group and host file data. Caching can be extremely valuable on servers that handle lots of logins, and is especially beneficial if you are authenticating your users against a directory server (it decreases the amount of traffic sent between hosts). Since nscd is unable to fill each and every request from cache, it has to periodically incur a cache miss. To see how often this occurs on a Solaris server, nscd can be run with the "-g" (print statistics) option: This is nifty!
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