Best of Technical Support

Our experts answer your technical questions.
Corrupted Root Filesystem

I am trying to install Red Hat onto my Dell laptop using the partition I created for it. The install runs successfully, but when I try to load Linux it hangs up after these messages:

checking root filesystem
/ was not cleanly unmounted, check forced
Setting filetype for entry log in /dev (174593) to 6
Unattached inode 82384
UNEXPECTED INCONSISTENCY; run fsck MANUALLY
(ie without -a or -p options)
An error occured during the filesystem check
Dropping you to a shell; the system will reboot
Give root password for maintenance

—Brian Weigner, brian.weigner@colorado.edu

Seems your Linux root filesystem was corrupted somehow. You actually need to get into single-user mode by issuing a linux s command at the LILO prompt and wait until you get the # root prompt. Type:

e2fsck -r /dev/your-root-disk-device

This will go through the device and ask you what to do with each error it finds. This will probably ask many questions that should be answered. To properly answer all of them, some Linux filesystem experience is a must. This is risky business on a real production system. For now, since it is a fresh install and to make it easy, answer yes to all the FIX?, and REPAIR? and REMOVE unused/dirty stuff, questions. After you are done, try rebooting your system. If that doesn't work, maybe your best bet is to carefuly reinstall. —Felipe E. Barousse Boué, fbarousse@piensa.com

To prevent this from happening in the future, run shutdown -h now (as root) before you power down. —Don Marti, dmarti@linuxjournal.com

FTP Users Go Ape! Virtual Hosts Fail!

My FTP users are able to back past their home directory and go right to /. They are using leach FTP, and it allows them to go up levels even in their home directory.

Also, I have 20 virtual sites (by name, not IP) running on my Apache server. A couple of times when adding a new virtual host, it would not resolve until I moved it to the top of the list of virtual hosts in httpd.conf. Am I out of virtual servers? The computer is an AMD K6 200MHz with 64MB of RAM. —Aaron, aaron@x56.net

There is a hack in wuftpd to prevent users from cd-ing up, but you are probably better off installing proftpd if you aren't using that yet. It supports chrooting users in their home directory or some other preset directory. See: http://www.proftpd.net/. —Marc Merlin, marc_bts@valinux.com

You're not out of virtual hosts, but this configuration can be tricky. Here are some things to check. Do any of the ServerName or ServerAlias values in the virtual hosts before the broken one match the broken one's name? If you have a ServerAlias *.example.com and add warez.example.com, it won't work. Keep everything with a * alias at the end. Do an nslookup to make sure that the DNS for all the virtual hosts works. Make sure that the NameVirtualHost directive is before the corresponding VirtualHost sections. Read httpd.apache.org/docs-2.0/vhosts/details.html and, of course, every webmaster's most-read and least-enjoyed reading material, error_log. —Don Marti, dmarti@linuxjournal.com

I Have No Dialtone, and I Must Dial

I have a PCTEL internal modem, and I got the drivers from linmodems.org and have installed them. The problem is the modem keeps on dialing with the message NO DIALTONE. I was able to connect only once and that was after trying for a long time. Also, the transfer rate wasn't what I was expecting. —Krishna, as_krishna@hotmail.com

Try to see if adding X1 in your AT init string makes a difference. —Marc Merlin, marc_bts@valinux.com

Spammers Fishing for Addresses

Increasingly, I see spammers attempting to send mail to my domains by simply trying a series of common first names (i.e., david@example.com, bill@example.com, mike@example.com, etc.) Is there any automated method of shutting down the connection after X failed addresses and, even better, adding their IP to sendmail's access database? —Waldo Jaquith, waldo@waldo.net

You could write a small Perl script that parses the reject log, adds the IP to a blacklist and restarts sendmail when this happens. —Marc Merlin, marc_bts@valinux.com

______________________

White Paper
Linux Management with Red Hat Satellite: Measuring Business Impact and ROI

Linux has become a key foundation for supporting today's rapidly growing IT environments. Linux is being used to deploy business applications and databases, trading on its reputation as a low-cost operating environment. For many IT organizations, Linux is a mainstay for deploying Web servers and has evolved from handling basic file, print, and utility workloads to running mission-critical applications and databases, physically, virtually, and in the cloud. As Linux grows in importance in terms of value to the business, managing Linux environments to high standards of service quality — availability, security, and performance — becomes an essential requirement for business success.

Learn More

Sponsored by Red Hat

White Paper
Private PaaS for the Agile Enterprise

If you already use virtualized infrastructure, you are well on your way to leveraging the power of the cloud. Virtualization offers the promise of limitless resources, but how do you manage that scalability when your DevOps team doesn’t scale? In today’s hypercompetitive markets, fast results can make a difference between leading the pack vs. obsolescence. Organizations need more benefits from cloud computing than just raw resources. They need agility, flexibility, convenience, ROI, and control.

Stackato private Platform-as-a-Service technology from ActiveState extends your private cloud infrastructure by creating a private PaaS to provide on-demand availability, flexibility, control, and ultimately, faster time-to-market for your enterprise.

Learn More

Sponsored by ActiveState