100 Linux Tips and Tricks

Tip 4: Display IP rather than hostname

When dealing with networking issues, it often helps to be able to use only IP addresses rather than hostnames. Why? For 2 reasons. First, the name server might not always be available if routing is being changed. And most important, you may not have the time to wait for all the IP resolving to be done.

Fortunately, many networking utilities in Linux share a common option flag. The -n flag. It will allow you to make the utility display IP addresses rather than hostnames. Here are a few examples:

netstat -an traceroute 1.2.3.4 -n

arp -n -a -i eth0 -a proxy

These commands were all given the -n flag and will display only IP addresses.

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100 Linux Tips and Tricks

Tip 5: Is my modem a winmodem?

Winmodems are modems which lack some hardware. They use software drivers to emulate the hardware, and the CPU to do some tasks. Unfortunately the drivers provided by the winmodem manufacturers are Windows only.

There is no sure way to know if the modem should work in Linux or not, except trying it yourself, or ask someone else who has tried it. Fortunately, there is a Web site with a very long list of modems that are known to work in Linux, and those that are winmodems. The Web site can be found at http://www.o2.net/~gromitkc/winmodem.html.

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100 Linux Tips and Tricks

Tip 6: Sharing files from a Windows system

The protocol to use to be able to share files with Windows systems is called SMB. Linux supports natively a lot of file systems and network protocols. SMB is one of them. To be able to mount a Windows file system to share files, that system needs to have file sharing enabled, and you need to enable SMB support in the kernel. You also need to download a program called Samba which allows you to share remote file systems, and build yourself a server. General information about how to connect Linux, Windows machines and Macs is on the Web at http://www.eats.com/linux_mac_win.html.

If SMB is not a possibility, you could use FTP. Linux by default has an FTP server turned on. Windows FTP servers are also available for free.

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100 Linux Tips and Tricks

Tip 7: Sorry but this host is not in my list

Mail clients require you to specify your server for incoming mail, but they also need a server for outgoing mail. If you have sendmail or Qmail running, you can use localhost. If not, you may use your provider's mail server.

If you setup your own mail server, you may have problems sending mail from other systems on your network. Mail servers often block clients from using them for outgoing mail to prevent relaying. You need to specify the hosts where you will be sending mail from. Here is how to do it in Qmail, from the FAQ. You need to put the following line in /etc/hosts.allow:

tcp-env: ip1, ip2, ip3: setenv = RELAYCLIENT

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