RH9: lost network connection
 

My laptop, which dual-boots RedHat 9 and Windows XP Pro has been running for about a year with no problems.

It connects to the internet through an SMC router and from there to my dsl modem.

Suddenly, today, it is having problems online in RedHat. It's not a hardware problem, because if I boot up Windows it can connect to the internet, download files, etc, with no difficulty. But under RedHat, I can't connect to any websites with Mozilla Firebird or Konqueror (or gFTP).

Two other computers are logged on through that router, one running XP, the other running RH9, both working perfectly. And on the router, the light indicating that the laptop is connected is lit as usual.

While booting up, the laptop displays:
Bringing up interface eth0 [OK]

The Network Configuration/Devices tab shows eth0 as active, and the /Hardware tab shows status ok for eth0.

Strangely, my Yahoo start page on the laptop is completely up to date; it displays the same news headlines and everything else exactly the same on the laptop as on the other machines, but click on any link and I get "weather.yahoo.com cannot be found", etc.

Also, a few times when I opened up Firefox, it gave me "my.yahoo.com cannot be found". Yet, a few minutes later, the start page is again displayed looking perfectly normal (except that most of the links still don't work.)

Any suggestions for what may be wrong?

can you try to resolve other addresses - using the command line -

e.g.
dig www.google.com OR
dig mail.linuxquestions.net OR
dig any linuxquestions.org

If these work well, you can be certain your nameserver resolutions are good.

Thanks ppuru.

It seems to be able to find a few addresses, but most cannot be found. For example (using the Firefox browser) I can go to www.my.yahoo.com and it displays current headlines, movie listings, stock indices, etc. I can click on a headline & it will open the article. I can click on, for example, NASDAQ, and it opens up the "Quotes & Info" page at finance.yahoo.com. I can go to my email folders.

A few minutes ago, when I tried clicking on movie listings, I was getting: movies.yahoo.com could not be found. But now, the movie links are working fine.

But if I click on a tv listing, I get: "tv.yahoo.com could not be found".

Oops, I just tried the movies again & I'm getting: "movies.yahoo.com could not be found."

On the other hand, weather.yahoo.com was working a few minutes ago, but just now I tried it and "weather.yahoo.com could not be found".

If I try to get into one of the folders in my yahoo briefcase:
" f2.pg.briefcase.yahoo.com could not be found". This one has been consistently unavailable since yesterday.

Enough about yahoo. Trying Google: I can open Google advanced search with no problem. I can do a search. For example, I just searched "bombay". I get like 4.3 million hits. If I click on any of the actual links I can't open them: i.e. "www.mumbainet.com could not be found", "www.litb.ac.in could not be found", etc. In every case, the google Cache of these pages opens up just find, but I can't open any of the links on those pages.

I found a few other addresses I can open,like www.abc.go.com, www.macromedia.com, and they seem to be working fine, including all the links I tried on those pages.

But on the other hand;
www.linuxquestions.org
www.physicsforums.com
www.cprogramming.com
nehe.gamedev.net
all of these "could not be found"

I tried your suggestion and at the terminal command line:
dig www.google.com
I got:
; <<>> DiG 9.2.1 <<>> www.google.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27196
;; flags: qr rd; QUERY: 1, ANSWER: 3, AUTHORITY: 11, ADDITIONAL: 2
(plus more information in an ANSWER SECTION, AUTHORITY SECTION, ADDITIONAL SECTION



I also tried
dig any www.linuxquestions.org
I got:
; <<>> DiG 9.2.1 <<>> any www.linuxquestions.org
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27894
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 0

;; QUESTION SECTION:
;www.linuxquestions.org IN ANY

;; AUTHORITY SECTION:
org. 14373 IN NS TLD1.ULTRADNS.NET.
org. 14373 IN NS TLD2.ULTRADNS.NET.

;; Query time: 19 msec
;; SERVER: 167.206.3.228#53 (167.206.3.228)
;; WHEN: Tue Aug 10 11:56:22 2004
;; MSG SIZE rdvd: 90


But remember that I am unable to bring up linuxquestions.org in either browser.

Finally, I opened up pine,and found that I CAN send email from that to my yahoo email account.

I have no idea what's going on here, but I really would like to understand (and fix) it. Can you help?

Problem seems to be solved; see here:
http://www.linuxquestions.org/questi...hreadid=216048

But a changing DHCP leased IP address does not seem to be your problem. You may still check how often your WAN IP changes.

Can you try changing the nameservers in your /etc/resolv.conf to 63.239.106.149. This is the secondarydns.org name server. Check if that resolves consistently. Also, can you check your resolv.conf - perhaps it has entries that point to not-so-consistent nameservers.

edit:
instead of changing resolv.conf, you can first try

dig any google.com @63.239.106.149
and other names. You may then try using the nameservers listed in your resolv.conf instead of the secondary.org nameserver.

Thanks ppuru.

I have already changed it to this:

; generated by /sbin/dhclient-script
nameserver 151.202.0.85
nameserver 151.203.0.85
search localdomain

which is the same as I found in my desktop machines. Everything now seems to work correctly.

Before I made this change, resolv.conf contained:
; generated by /sbin/dhclient-script
nameserver 167.206.3.228
nameserver 167.206.3.227
nameserver 167.206.3.162
search localdomain

I don't know how (or when) those entries got there.

Depending on the distro you use, you can set a parameter or use the -R flag to prevent dhcp from (re)setting your /etc/resolv.conf.

RedHat/Fedora/Mandrake/ orhter RedHat based distros, set PEERDNS to no in /etc/sysconfig/network-scripts/ifcfg-<nic>

Otherwise you will need to look into the startup/boot scripts for the dhcpcd line and add the -R option.

Hmmm.. this is really puzzling.

I just looked at /etc/sysconfig/network-scripts/ifcfg-eth0 and it has the entry PEERDNS=no
and that file has not changed since last October.

So, does that mean that /etc/resolv.conf should NOT change even when I change locations (and internet connections)?

If so, then the mystery is when and how did I get those problem entries
nameserver 167.206.3.228
nameserver 167.206.3.227
nameserver 167.206.3.162
in there? Unfortunately, I didn't look at the date of the file before I edited it, so I don't know when it changed. I guess I'll just have to watch it over the next few weeks & see what happens.

Thanks for your help.

PS: do those 167... addresses seem at all familiar to you?

/etc/resolv.conf should not change even if you change your ISP.

I ran a whois on the 167 IPs and they come up with

Cablevision Systems Corp. CVNET (NET-167-206-0-0-1)
167.206.0.0 - 167.206.255.255
Cablevision CVNET-A7CE0200 (NET-167-206-2-0-1)
167.206.2.0 - 167.206.3.255

Well, that those nameservers belong to Cablevision sort of makes sense. I don't remember for sure, but it's possible that I was connected to their network when I did that RedHat9 installation on the laptop. And maybe the trouble I was experiencing was due to trouble in their system. Maybe they don't even use those nameservers any more. Anyway, the ones I switched to last night belong to Verizon, which is my current ISP, and everything is working fine.

But this puzzles me:
Isn't the nameserver a service provided by each ISP? So, are you telling me that anybody can use any nameserver, regardless of who his ISP is?