Redhat 7.2 upgrade caveats

According to Bruno Guerreiro (thanks for telling me!) the 7.1 notes on sendmail is applicable to 7.2 as well:

Redhat 7.1 upgrade caveats

Here are some things that stopped working when I upgraded to redhat 7.1 (custom install) from 6.2. Hopefully google or some other search engine will pick these notes up, so that it will save other people the trouble of figuring it out for themselves. (I guess it worked, so far about 29 people emailed me to say thanks.)

Sendmail

It seems like the default sendmail behaviour has been changed to only accept connections from localhost. This means that mail sent from other machines will bounce, and if you dig deep enough in the mail logs the reason given is "connection refused". (Rant: This is rather idiotic, if I install sendmail on my box it means that I really want to be able to receive mail from the world! Since inetd has been replaced by xinetd, and there are some firewalls turned on, it took me forever to figure out that a changed sendmail.mc was the reason.)

Fix: In /etc/mail/sendmail.mc, change the line

DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

to

dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

and run

m4 /etc/mail/sendmail.mc > /etc/sendmail.cf

Then run /etc/rc.d/init.d/sendmail restart

Secure shell

Redhat 7.1 comes with OpenSSH. When connecting to machines running the old SSH 1, everything works. However, two OpenSSH boxes will ignore the public key in ~/.ssh/authorized_keys, forcing you to type in your password again and again.

Fix: Run

ssh-keygen -t dsa

and then move the key in ~/.ssh/id_dsa.pub to ~/.ssh/authorized_keys2 (on the host you are connecting to.)

Stupid thing to watch out for: make sure ~/.ssh/authorized_keys2 is writable only by you, otherwise openssh refuses to use the key. (This is correct behavior, but it would be nice if I was informed of it, at least when connecting with ssh -v (i.e., verbose).)

IBM Thinkpad 570E

There is something fishy with the power management. Once in a while when I suspend the laptop with apm -s, the machine hangs. I have not yet figured out how to fix it. Spurious X lockups. I finally got rid of them by adding the following options to /etc/X11/XF86Config-4: 

Section "Screen"
    Identifier "screen1"
    Device      "NeoMagic (laptop/notebook)"
    Monitor     "Generic|Generic Laptop Display Panel 1024x768"

# hopefully this gets rid of X lockups
    Option "XaaNoScanlineImageWriteRect"
    Option "XaaNoScanlineCPUToScreenColorExpandFill"
(Note: I am now running Mandrake 8.1 so it might not apply to RH6.2/7.1 I should make a new page on Mandrake troubles.)