Sudden problem with LAN access to some of the net

[Claude Jones]

This problem has so stumped me I don't know if I can fairly describe it, but I 
post what I can here to see if it strikes a chord with anyone else. My 
scenario is an FC4 machine that is right on the net - I use this as my home 
machine and it is mostly for experimentation and email. I use FWBuilder to 
protect it. It serves as dhcp server to several pc's in my home all running 
Windows. All has been working well for months. Two nights ago, I was trying 
to get bittorrent to work and was experimenting with opening various ports. 
That same night I did some updates. That's a poor description, I realize, but 
it is just to set the stage. The next morning, two of the pc's on my Lan had 
lost some of their connectivity. My wife's laptop, for example, couldn't get 
email or run messenger - just returned 'couldn't connect' messages. However, 
she could still browse websites. Similar problems with a second pc that I 
don't have much access to, so I can't be specific but, he couldn't get mail. 
Two other pc's continued to function normally. I fired up an old laptop I 
keep here for testing, and it connected and all functions worked. 

So -- dhcp is working - the problem machines are getting valid addresses - 
they continue to have some functionality
I suspect an issue with DNS - I had set up a DNS server on my FC4 box months 
ago, and it has been working well - dhcp gives out 127.0.0.1 as the dns 
server to the lan machines - what I did to fix the problem was to change that 
entry in dhcp to my isp's DNS server - presto, things started working...

So, any ideas on what I could have broken with my DNS configuration? 
-- 
Claude Jones
Bluemont, VA, USA

[Bob Chiodini]

On Thu, 2005-09-29 at 08:53 -0400, Claude Jones wrote:
>  This problem has so stumped me I don't know if I can fairly
> describe it, but I 
>  post what I can here to see if it strikes a chord with anyone else. My 
>  scenario is an FC4 machine that is right on the net - I use this as my home 
>  machine and it is mostly for experimentation and email. I use FWBuilder to 
>  protect it. It serves as dhcp server to several pc's in my home all running 
>  Windows. All has been working well for months. Two nights ago, I was trying 
>  to get bittorrent to work and was experimenting with opening various ports. 
>  That same night I did some updates. That's a poor description, I realize, but 
>  it is just to set the stage. The next morning, two of the pc's on my Lan had 
>  lost some of their connectivity. My wife's laptop, for example, couldn't get 
>  email or run messenger - just returned 'couldn't connect' messages. However,
>
>  she could still browse websites. Similar problems with a second pc that I 
>  don't have much access to, so I can't be specific but, he couldn't get mail.
>
>  Two other pc's continued to function normally. I fired up an old laptop I 
>  keep here for testing, and it connected and all functions worked. 
>  
>  So -- dhcp is working - the problem machines are getting valid addresses - 
>  they continue to have some functionality
>  I suspect an issue with DNS - I had set up a DNS server on my FC4 box months 
>  ago, and it has been working well - dhcp gives out 127.0.0.1 as the dns 
>  server to the lan machines - what I did to fix the problem was to change that 
>  entry in dhcp to my isp's DNS server - presto, things started working...
>  
>  So, any ideas on what I could have broken with my DNS configuration? 
>  -- 
>  Claude Jones
>  Bluemont, VA, USA
>   
Claude,

127.0.0.1 is the IP address the lo device on all machines in your net.
This may be some kind of special case, but I think your DHCP server
should hand out the real LAN address of your DNS server, something like
192.168.x.y.  Why it worked up until recently I don't know.

Bob...

[Claude Jones]

On Thursday 29 September 2005 10:27 am, Bob Chiodini wrote:
>  Claude,
>
>  127.0.0.1 is the IP address the lo device on all machines in your net.
>  This may be some kind of special case, but I think your DHCP server
>  should hand out the real LAN address of your DNS server, something like
>  192.168.x.y.  Why it worked up until recently I don't know.
>
>  Bob... 
Thanks, Bob - and the other question which is why did it stop working only
for 
some functions (mail, messenger), and on only two PC's out 5? That's why I 
worded my opening sentence the way I did - one other thing I've noticed this 
am, is that I'm getting slpd errors on shutdown - well, it just says it 
failed to shut it down - I had never heard of this daemon, but I read a 
little about it, and on cursory inspection, it seems like it 'could' be 
related -- need to keep looking - I just posted this in case anyone else was 
having the same issue, on the chance it could be related to recent updates...
-- 
Claude Jones
Bluemont, VA, USA

[Bob Chiodini]

On Thu, 2005-09-29 at 13:15 -0400, Claude Jones wrote:
>  On Thursday 29 September 2005 10:27 am, Bob Chiodini wrote:
>  > Claude,
>  >
>  > 127.0.0.1 is the IP address the lo device on all machines in your net.
>  > This may be some kind of special case, but I think your DHCP server
>  > should hand out the real LAN address of your DNS server, something like
>  > 192.168.x.y.  Why it worked up until recently I don't know.
>  >
>  > Bob...
>  Thanks, Bob - and the other question which is why did it stop working only for 
>  some functions (mail, messenger), and on only two PC's out 5? That's why I 
>  worded my opening sentence the way I did - one other thing I've noticed this 
>  am, is that I'm getting slpd errors on shutdown - well, it just says it 
>  failed to shut it down - I had never heard of this daemon, but I read a 
>  little about it, and on cursory inspection, it seems like it 'could' be 
>  related -- need to keep looking - I just posted this in case anyone else was 
>  having the same issue, on the chance it could be related to recent updates...
>  -- 
>  Claude Jones
>  Bluemont, VA, USA
>   
Claude,

I'm running FC3 and do not have slpd, but glanced at the RFC.  Has there
been a slpd update lately?

Bob...

[Claude Jones]

On Thursday 29 September 2005 1:54 pm, Bob Chiodini wrote:
>  Claude,
>
>  I'm running FC3 and do not have slpd, but glanced at the RFC.  Has there
>  been a slpd update lately?
>
>  Bob... 
Just checked the home box. The only thing that got updated were 
not-possibly-related things like mplayer and lame - I'm not sure about one 
thing tho - I recently installed smartpm and started using it periodically. I 
can't seem to find any logs for it's activities. Still looking... I may have 
updated something that way, and it's not showing up in the yum.log file. 
Smart uses my yum repos, but I don't know how it deals with logging. 
-- 
Claude Jones
Bluemont, VA, USA

[Claude Jones]

On Thursday 29 September 2005 1:54 pm, Bob Chiodini wrote:
>  On Thu, 2005-09-29 at 13:15 -0400, Claude Jones wrote:
>  > On Thursday 29 September 2005 10:27 am, Bob Chiodini wrote:
>  > > Claude,
>  > >
>  > > 127.0.0.1 is the IP address the lo device on all machines in your net.
>  > > This may be some kind of special case, but I think your DHCP server
>  > > should hand out the real LAN address of your DNS server, something like
>  > > 192.168.x.y.  Why it worked up until recently I don't know.
>  > >
>  > > Bob...
>  >
>  > Thanks, Bob - and the other question which is why did it stop working
>  > only for some functions (mail, messenger), and on only two PC's out 5?
>  > That's why I worded my opening sentence the way I did - one other thing
>  > I've noticed this am, is that I'm getting slpd errors on shutdown - well,
>  > it just says it failed to shut it down - I had never heard of this
>  > daemon, but I read a little about it, and on cursory inspection, it seems
>  > like it 'could' be related -- need to keep looking - I just posted this
>  > in case anyone else was having the same issue, on the chance it could be
>  > related to recent updates... --
>  > Claude Jones
>  > Bluemont, VA, USA
>
>  Claude,
>
>  I'm running FC3 and do not have slpd, but glanced at the RFC.  Has there
>  been a slpd update lately?
>
>  Bob... 
Bob: I did some more checking when I got home last night. Still couldn't
find 
any record of slpd updates. Status indicates that it's running. I get the 
'failed to close' message when I shut down - don't know what that's about.


I got things working, again. Two things - the first was to enter the DNS 
servers from my ISP in my dhcp.conf file. That immediately brought all 
machines back to life. Then, I changed that entry to the address of my lan 
NIC, 192.168.2.1 as opposed to 127.0.0.1 - it seems to be continuing to work. 
It's a bit of a mystery - why it worked before, and why it stopped working 
for two pc's out of 5??? 

I was looking through the DNS bind server settings with Webmin last night, and 
I realized that there's a lot there I still don't understand - more reading 
to do... Thanks for the suggestions. 
-- 
Claude Jones
Bluemont, VA, USA

[Bob Chiodini]

On Fri, 2005-09-30 at 10:31 -0400, Claude Jones wrote:
>  On Thursday 29 September 2005 1:54 pm, Bob Chiodini wrote:
>  > On Thu, 2005-09-29 at 13:15 -0400, Claude Jones wrote:
>  > > On Thursday 29 September 2005 10:27 am, Bob Chiodini wrote:
>  > > > Claude,
>  > > >
>  > > > 127.0.0.1 is the IP address the lo device on all machines in your net.
>  > > > This may be some kind of special case, but I think your DHCP server
>  > > > should hand out the real LAN address of your DNS server, something like
>  > > > 192.168.x.y.  Why it worked up until recently I don't know.
>  > > >
>  > > > Bob...
>  > >
>  > > Thanks, Bob - and the other question which is why did it stop working
>  > > only for some functions (mail, messenger), and on only two PC's out 5?
>  > > That's why I worded my opening sentence the way I did - one other thing
>  > > I've noticed this am, is that I'm getting slpd errors on shutdown -
> well,
>  > > it just says it failed to shut it down - I had never heard of this
>  > > daemon, but I read a little about it, and on cursory inspection, it seems
>  > > like it 'could' be related -- need to keep looking - I just posted
> this
>  > > in case anyone else was having the same issue, on the chance it could be
>  > > related to recent updates... --
>  > > Claude Jones
>  > > Bluemont, VA, USA
>  >
>  > Claude,
>  >
>  > I'm running FC3 and do not have slpd, but glanced at the RFC.  Has there
>  > been a slpd update lately?
>  >
>  > Bob...
>  Bob: I did some more checking when I got home last night. Still couldn't find 
>  any record of slpd updates. Status indicates that it's running. I get the 
>  'failed to close' message when I shut down - don't know what that's
> about. 
>  
>  I got things working, again. Two things - the first was to enter the DNS 
>  servers from my ISP in my dhcp.conf file. That immediately brought all 
>  machines back to life. Then, I changed that entry to the address of my lan 
>  NIC, 192.168.2.1 as opposed to 127.0.0.1 - it seems to be continuing to work. 
>  It's a bit of a mystery - why it worked before, and why it stopped working 
>  for two pc's out of 5??? 
>  
>  I was looking through the DNS bind server settings with Webmin last night, and 
>  I realized that there's a lot there I still don't understand - more reading 
>  to do... Thanks for the suggestions. 
>  -- 
>  Claude Jones
>  Bluemont, VA, USA 
Claude,

Had the three working PCs been rebooted lately?  If not that might
explain why they continued to work.  Or they had not gotten new leases
from the server.

Maybe something mucked up you dhcp.conf file.  I've only limited
experience with DHCP, and I did not run my own DNS server, just handed
out the addresses from my ISP.  Is there a dhcp.conf.rpmnew or .orig
file?

Maybe there is a bug in webmin.  Did you happen to note the file date
and times for your dhcp.conf before changing it?

I take it that no one else is having similar problems.

Bob...

[Claude Jones]

On Fri September 30 2005 11:21 am, Bob Chiodini wrote:
>  Claude,
>
>  Had the three working PCs been rebooted lately?  If not that might
>  explain why they continued to work.  Or they had not gotten new leases
>  from the server.
>  
I booted a spare laptop that had been sitting on the shelf for months during 
this little episode, and it had no problems, so I don't think that's it. 

>  Maybe something mucked up you dhcp.conf file.  I've only limited
>  experience with DHCP, and I did not run my own DNS server, just handed
>  out the addresses from my ISP.  Is there a dhcp.conf.rpmnew or .orig
>  file?
>  
dhcp.conf was intact - I did check that

>  Maybe there is a bug in webmin.  Did you happen to note the file
> date
>  and times for your dhcp.conf before changing it?
>  
well, I don't know about that - I had been poking around webmin that night, 
but I didn't configure anything with it - 

>  I take it that no one else is having similar problems. 
no one
else has chimed in
I did notice one other thing regarding slpd; on boot I get a selinux message 
saying it has failed to get permissions - I can't give details because I'm on 
my way out of town

Hope this current configuration 'holds' - my downstairs housemate wouldn't 
want internet down for a whole weekend - fortunately, I have a router that 
can be swapped in for my Linux box, and I left him instructions on how to do 
that - I guess I'm in wait and see mode

-- 
Claude Jones
Bluemont, VA, USA

[Bob Chiodini]

On Fri, 2005-09-30 at 18:38 -0400, Claude Jones wrote:
>  On Fri September 30 2005 11:21 am, Bob Chiodini wrote:
>  > Claude,
>  >
>  > Had the three working PCs been rebooted lately?  If not that might
>  > explain why they continued to work.  Or they had not gotten new leases
>  > from the server.
>  >
>  I booted a spare laptop that had been sitting on the shelf for months during 
>  this little episode, and it had no problems, so I don't think that's it. 
>  
>  > Maybe something mucked up you dhcp.conf file.  I've only limited
>  > experience with DHCP, and I did not run my own DNS server, just handed
>  > out the addresses from my ISP.  Is there a dhcp.conf.rpmnew or .orig
>  > file?
>  >
>  dhcp.conf was intact - I did check that
>  
>  > Maybe there is a bug in webmin.  Did you happen to note the file date
>  > and times for your dhcp.conf before changing it?
>  >
>  well, I don't know about that - I had been poking around webmin that night, 
>  but I didn't configure anything with it - 
>  
>  > I take it that no one else is having similar problems.
>  no one else has chimed in
>  I did notice one other thing regarding slpd; on boot I get a selinux message 
>  saying it has failed to get permissions - I can't give details because I'm on 
>  my way out of town
>  
>  Hope this current configuration 'holds' - my downstairs housemate wouldn't 
>  want internet down for a whole weekend - fortunately, I have a router that 
>  can be swapped in for my Linux box, and I left him instructions on how to do 
>  that - I guess I'm in wait and see mode
>  
>  -- 
>  Claude Jones
>  Bluemont, VA, USA
>   
Claude,

This may be rendered to a mystery of life, if it does not recur.  But,
if it does disable slpd and wait and see.  Not the most timely way of
troubleshooting.

Bob...