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 wget http://li.nux.ro/download/nux/misc/el6/x86_64/pdnsd-1.2.9a-par.x86_64.rpm yum install pdnsd-1.2.9a-par.x86_64.rpm cp /etc/pdnsd.conf.sample /etc/pdnsd.conf Edit the /etc/pdnsd.conf file.  Under server, change the ip value to your DNS server. server { label= “myisp”; ip = 192.168.1.1,8.8.8.8; # Put your ISP’s DNS-server…

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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…

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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…

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