C2T2 -- X from older RedHat install, external WWW access

[Darryl Gamble]

I've just installed Fedora C2T2 and it is working quite well for most 
things.

I have two issues that have me stumped.

1.  Trying to start an xterm on fedora_test from an old RedHat 7.2 
installation.   I get the message:
"xterm Xt error: Can't open display <fedora_test>:0"
Is this an X authentication error related to having older versions 
writing to Xauth?   Is there an easy fix for it?
BTW When I ssh to the same machine and do an xterm through DISPLAY 
<redhat_72>:10.0 it works properly.

2.  Access to external web sites fails.   Web sites on the same subnet 
work alright and I am able to ping external web site names.
 However telnet's to port 80 or mozilla web access fails with a timeout 
(either by name or bu IP address).
Interestingly I was working fine under C2T1 *until* I upgraded my kernel 
through up2date from the 2.6.1 release to the 2.6.3 release (the default 
kernel in C2T2).  (BTW I have set selinux=disabled for these tests and 
disabled the firewall).
What should I look at in the kernel that might be causing this issue?  
(an IPv6 vs IPv4 problem?)
I am currently using kernel 2.6.3-2.1.253.2.1 and can not get external 
access.  Can someone help me out and point me in the right direction?

Thank you,
Darryl

[Alan Cox]

On Thu, Apr 01, 2004 at 04:02:00PM -0500, Darryl Gamble wrote:
>  1.  Trying to start an xterm on fedora_test from an old RedHat 7.2 
>  installation.   I get the message:
>  "xterm Xt error: Can't open display <fedora_test>:0" 
Gdm defaults to running X with tcp disabled, so that local or ssh
secure forwarding are the only choice.

>  Is this an X authentication error related to having older versions 
>  writing to Xauth?   Is there an easy fix for it? 
gdmconfig 

>  2.  Access to external web sites fails.   Web sites on the same
> subnet 
>  work alright and I am able to ping external web site names.
>  I am currently using kernel 2.6.3-2.1.253.2.1 and can not get external 
>  access.  Can someone help me out and point me in the right direction? 
Check the default route is set right, if it seems to be then turning off
ECN might give some clues. As might tcpdump

[Darryl Gamble]

Thanks very much Alan.

1. I found that /usr/sbin/gdmconfig was set to disallow TCP traffic from 
the Security tab.   I've turned that off.

2. You mentioned that I should turn off ECN given that my default route 
is working alright.   I believe it is working properly given that I can 
ping www.yahoo.com.   I tried that using "echo 0 > 
/proc/sys/net/ipv4/tcp_ecn" and low and behold my telnet to port 80 works!
I am now assuming that one of my ISPs routers is failing on the ECN.   
Is there an easy way to check which router is causing the failure?

Darryl

Alan Cox wrote:

> On Thu, Apr 01, 2004 at 04:02:00PM -0500, Darryl Gamble wrote:
>   
>
> >1.  Trying to start an xterm on fedora_test from an old RedHat 7.2 
> >installation.   I get the message:
> >"xterm Xt error: Can't open display <fedora_test>:0"
> >    
> >
>
> Gdm defaults to running X with tcp disabled, so that local or ssh
> secure forwarding are the only choice.
>
>   
>
> >Is this an X authentication error related to having older versions 
> >writing to Xauth?   Is there an easy fix for it?
> >    
> >
>
> gdmconfig 
>
>   
>
> >2.  Access to external web sites fails.   Web sites on the same subnet 
> >work alright and I am able to ping external web site names.
> >I am currently using kernel 2.6.3-2.1.253.2.1 and can not get external 
> >access.  Can someone help me out and point me in the right direction?
> >    
> >
>
> Check the default route is set right, if it seems to be then turning off
> ECN might give some clues. As might tcpdump
>
>
>
>   
>