Linux – How to get ldapsearch on Scientific Linux

Short answer: you can't. Ports below 1024 can be opened only by root. As per comment - well, you can, using CAP_NET_BIND_SERVICE, but that approach, applied to java bin will make any java program to be run with this setting, which is undesirable, if not a security risk.

The long answer: you can redirect connections on port 80 to some other port you can open as normal user.

Run as root:

# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080

As loopback devices (like localhost) do not use the prerouting rules, if you need to use localhost, etc., add this rule as well (thanks @Francesco):

# iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-ports 8080

NOTE: The above solution is not well suited for multi-user systems, as any user can open port 8080 (or any other high port you decide to use), thus intercepting the traffic. (Credits to CesarB).

EDIT: as per comment question - to delete the above rule:

# iptables -t nat --line-numbers -n -L

This will output something like:

Chain PREROUTING (policy ACCEPT)
num  target     prot opt source               destination         
1    REDIRECT   tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:8080 redir ports 8088
2    REDIRECT   tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:80 redir ports 8080

The rule you are interested in is nr. 2, so to delete it:

# iptables -t nat -D PREROUTING 2

Download the package(s) and type rpm -Uvh <packagenames> as root or sudo rpm -Uvh <packagenames> as normal user

I used rpm -qpR yum-3.2.27-14.el6.noarch.rpm to get a list of dependencies for yum, hope that gets all off them in one go:

Download all the packages with the following code block:

wget http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/python-2.6.5-3.el6.x86_64.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/python-libs-2.6.5-3.el6.x86_64.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/pygpgme-0.1-18.20090824bzr68.el6.x86_64.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/python-urlgrabber-3.9.1-7.el6.noarch.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/python-pycurl-7.19.0-5.el6.x86_64.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/rpm-python-4.8.0-12.el6.x86_64.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/yum-3.2.27-14.el6.noarch.rpm \
http://ftp2.scientificlinux.org/linux/scientific/6.0/x86_64/os/Packages/yum-metadata-parser-1.1.2-14.1.el6.x86_64.rpm

Install them as follows:

rpm -Uhv py*.rpm \
   yum*.rpm \
   rpm-py*.rpm