Tag: nslookup

Install and use pdnsd for name service caching

The man pages describe pdnsd as a dns proxy daemon capable of saving the contents of its DNS cache to the disk on exit. The Install Edit the /etc/pdnsd.conf file. ¬†Under server, change the ip value to your DNS server. Edit the /etc/resolv.conf to point the server to itself. For my test, I commented out everything and only added the...Read More »

Install and use ncsd for name service caching

According to Red Hat, "[t]he Name Service Caching Daemon (nscd) is a service that runs in the background and keeps a copy of /etc/passwd, /etc/group, [/etc/netgroup, /etc/services] and /etc/hosts files in /var/db/nscd/ directory. This can aid performance by reducing disk read overhead on a heavily loaded system dealing with many logins or name resolution requests." The installation and usage is...Read More »

Sorting Through Results of Revolving IPs from nslookup Results

If you are using something like imap.mail.yahoo.com or outlook.office365.com and would like to add a firewall rule to open the appropriate IPs to access could be quite a challenge. These IPs seem to change often. Here are a couple of command lines that may help sort through this mess. Typically, a simple command would be executed with results. nslookup outlook.office365.com...Read More »