terrible ping and DNS
Andrzej Pinczuk
I configured DNS server (sco 5.0.5). All fine works but...
When I reboot server and I try ping from other hosts
by IP (not by domain !) adress, it looks like:
ttl=64 time=0
ttl=64 time=3030
ttl=64 time=6060
ttl=64 time=9090
(time is still increasing by value 3030)
etc., etc.
Files resolv.conf contains:
domain .
nameserver 10.9.0.11
hostresorder bind local
More info:
1. When line "hostresorder" no exists,
ping by IP doesn't work !
2. When I stop DNS server by /etc/ndc stop
ale is OK (problem appears when I reboot/turn off computer).
Where is problem ?
Andy
Richard Gliebe
"Andrzej Pinczuk" <an...@send.pl> wrote in message
news:l7u2husk77gkjcdgb...@4ax.com...
don't know :) but try something.
1. delete in /etc/resolv.conf the line "domain ."
2. change the hostresorder to "local bind"
3. change "nameserver 10.9.0.11" to "nameserver 127.0.0.1", but only in
the /etc/resolv.conf on the DNS Server.
rigl
Andrzej Pinczuk
Thanks for your answer.
>1. delete in /etc/resolv.conf the line "domain ."
When I did it, computers can't connect with
DNS server. For example "ping test"
returns "unknow hosts".
BTW ping (by IP) to others hosts doesn't work correctly too
(od course when computer with DNS server is turned off).
>2. change the hostresorder to "local bind"
No positive results.
>3. change "nameserver 10.9.0.11" to "nameserver 127.0.0.1", but only in
>the /etc/resolv.conf on the DNS Server.
No positive results too :-(
Perhaps any more ideas ?
Andy
Richard Gliebe
"Andrzej Pinczuk" <an...@send.pl> wrote:
> Thanks for your answer.
>
> >1. delete in /etc/resolv.conf the line "domain ."
>
> When I did it, computers can't connect with
> DNS server. For example "ping test"
> returns "unknow hosts".
>
> BTW ping (by IP) to others hosts doesn't work correctly too
> (od course when computer with DNS server is turned off).
OK, change "domain ." to "domain <yourdomain.com>
> >2. change the hostresorder to "local bind"
>
> No positive results.
>
> >3. change "nameserver 10.9.0.11" to "nameserver 127.0.0.1", but only in
> >the /etc/resolv.conf on the DNS Server.
>
> No positive results too :-(
on your DNS server, you can leave this entry "nameserver 127.0.0.1"
> Perhaps any more ideas ?
try from another machine:
"ping yourdns.yourdomain.com"
rigl
Adrian de los Santos
on your DNS
nslookup
returns ?
On Thu, 20 Jun 2002 14:15:26 +0200, Andrzej Pinczuk <an...@send.pl>
wrote:
Jeff Liebermann
wrote:
>Hello
I just had the same problem in my office precipitated by replacing my
Linux based firewall, with a Watchguard SOHO router/firewall.
It took two cups of coffee to figure out what I broke. What happened
is that I had the cacheing DNS server in the Linux firewall set as the
first DNS nameserver in my resolv.conf. The Watchguard does NOT have
a DNS cache. I guess(tm) it takes exactly one second for ping to
decide that the first nameserver is not returning anything useful and
go on to the 2nd nameserver line.
One difference is that my delays were exactly 1 second instead of your
3 second delays. My guess(tm) is that your OSR5 box is trying 3 times
before blundering onward, while my 3.2v4.2 box only tries once.
I don't understand why ping insists on doing a lookup on every packet,
even for ping by IP address. My guess(tm) is that ping is doing a
reverse DNS lookup and that's failing. I could dig out the sniffer
and be sure, but not this week. Therefore my guess(tm) is that your
internal nameserver at 10.9.0.1 is having a bad day and is comatose.
See if temporarily replaceing that nameserver with a real outside DNS
server fixes the problem.
Incidentally, my resolv.conf resolution order looks like this:
hostresorder local bind
I had to put my internal hosts in /etc/hosts to prevent telnet and ftp
login delays caused by an unwanted server reverse DNS lookup. With
the reversed order, I found that my system was doing numerous wasted
DNS lookups to the various outside nameservers before decideing to
lookup the name/ip in /etc/hosts.
Disclaimer: There's an awful lot of guesswork in the above.
--
Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
(831)421-6491 pgr (831)426-1240 fax (831)336-2558 home
http://www.LearnByDestroying.com WB6SSY
je...@comix.santa-cruz.ca.us je...@cruzio.com
Andrzej Pinczuk
>
>on your DNS
>
>nslookup
>
>returns ?
If on machine with DNS server exists resolv.conf,
nslookup from this computer returns
"Can't find server names for address 10.9.0.11: server failed
Deafault server not available"
If on machine with DNS no exists resolv.conf,
nslookup from this computer returns
"default server: scosysv
address: 0.0.0.0"
But DNS server works correctly.
Andy
Andrzej Pinczuk
>I don't understand why ping insists on doing a lookup on every packet,
>even for ping by IP address.
Exactly.
In my opinion problem isn't DNS server
because all work perfectly during server
is turn on. I think problem is with others
computers. I don't understand why
(when machine with DNS server is turned off)
all computers looks for dns - even by IP.
And why 3030 time.
Andy
Bela Lubkin
> Jeff Liebermann <je...@comix.santa-cruz.ca.us> napisa3(a):
>
> >I don't understand why ping insists on doing a lookup on every packet,
> >even for ping by IP address.
>
> Exactly.
> In my opinion problem isn't DNS server
> because all work perfectly during server
> is turn on. I think problem is with others
> computers. I don't understand why
> (when machine with DNS server is turned off)
> all computers looks for dns - even by IP.
> And why 3030 time.
The problem is that your DNS servers are not responding to reverse DNS
lookups. Try:
nslookup -type=any 100.0.0.10.in-addr.arpa
(substitute the actual IP address of the machine you are pinging, in
reversed-octet order; i.e. if you're pinging 10.9.8.7, nslookup
-type=any 7.8.9.10.in-addr.arpa). This should give you a report showing
the name associated with that IP address. If it doesn't, your reverse
DNS is misconfigured.
3030ms is because there's a 1-second timeout on the lookups, and you
have more than one DNS server listed in /etc/resolv.conf, or the first
server that's being contacted is telling ping to ask a second & third
server. Plus about 10ms overhead per query.
Ping does lookups on every packet because it's a diagnostic tool and
intends to show you things like dynamic changes in DNS. If you ping the
same IP address for a very long time, and record the results, and
someone changes that host's name in the middle of the recording, the
change will show up.
>Bela<
Andrzej Pinczuk
>(substitute the actual IP address of the machine you are pinging, in
>reversed-octet order; i.e. if you're pinging 10.9.8.7, nslookup
>-type=any 7.8.9.10.in-addr.arpa). This should give you a report showing
>the name associated with that IP address. If it doesn't, your reverse
>DNS is misconfigured.
I have "unknow query type 10.9.0.1.in-addr.arpa"
What can I do to eliminate
this problem ? Sometimes I must turn off my major computer
(with DNS server) for few hours. Some of others computers in my
net have installed sco 3.2, where I can't write more nameservers
in resolv.conf (limit by the sco 3.2 version).
Is any solution to correct work others machines when DNS server is shutdowned ?
Andy
Bela Lubkin
> Bela Lubkin <be...@caldera.com> wrote:
>
> >(substitute the actual IP address of the machine you are pinging, in
> >reversed-octet order; i.e. if you're pinging 10.9.8.7, nslookup
> >-type=any 7.8.9.10.in-addr.arpa). This should give you a report showing
> >the name associated with that IP address. If it doesn't, your reverse
> >DNS is misconfigured.
>
> I have "unknow query type 10.9.0.1.in-addr.arpa"
I think you made a syntax error. Try:
nslookup -type=any 10.9.0.1.in-addr.arpa
> What can I do to eliminate
> this problem ? Sometimes I must turn off my major computer
> (with DNS server) for few hours. Some of others computers in my
> net have installed sco 3.2, where I can't write more nameservers
> in resolv.conf (limit by the sco 3.2 version).
> Is any solution to correct work others machines when DNS server is shutdowned ?
If your DNS server is sometimes down, you could put the name/IP
translations for your machines into /etc/hosts and use "hostresorder
local bind". I forget what the equivalent statement is for SCO Unix
3.2v4.2, but there was a way to get it to check /etc/hosts before DNS.
>Bela<
Jeff Liebermann
wrote:
>Andrzej Pinczuk wrote:
>
>> Bela Lubkin <be...@caldera.com> wrote:
>>
>> >(substitute the actual IP address of the machine you are pinging, in
>> >reversed-octet order; i.e. if you're pinging 10.9.8.7, nslookup
>> >-type=any 7.8.9.10.in-addr.arpa). This should give you a report showing
>> >the name associated with that IP address. If it doesn't, your reverse
>> >DNS is misconfigured.
>>
>> I have "unknow query type 10.9.0.1.in-addr.arpa"
>
>I think you made a syntax error. Try:
>
> nslookup -type=any 10.9.0.1.in-addr.arpa
Try:
nslookup -type=ANY 1.0.0.11.in-addr.arpa
The ANY must be upper case and the IP address must be reversed.
Sample output to see if one PBI nameserver knows about their other
nameservers. 206.13.28.12 is the local PBI DNS server while
the target 206.13.31.12 is their DNS server is Sacramento. Looks like
they fixed it.
=> nslookup -type=ANY 12.31.13.206.in-addr.arpa
Server: dns1-sf.snfc21.pacbell.net
Address: 206.13.28.12
Non-authoritative answer:
12.31.13.206.in-addr.arpa name = dns1-sac.scrm01.pacbell.net
Authoritative answers can be found from:
31.13.206.in-addr.arpa nameserver = NS1.PBI.net
31.13.206.in-addr.arpa nameserver = NS2.PBI.net
NS1.PBI.net internet address = 206.13.28.11
NS2.PBI.net internet address = 206.13.29.11
>> What can I do to eliminate
>> this problem ? Sometimes I must turn off my major computer
>> (with DNS server) for few hours. Some of others computers in my
>> net have installed sco 3.2, where I can't write more nameservers
>> in resolv.conf (limit by the sco 3.2 version).
>> Is any solution to correct work others machines when DNS server is shutdowned ?
>
>If your DNS server is sometimes down, you could put the name/IP
>translations for your machines into /etc/hosts and use "hostresorder
>local bind". I forget what the equivalent statement is for SCO Unix
>3.2v4.2, but there was a way to get it to check /etc/hosts before DNS.
>
>>Bela<
I add all my local machines into /etc/hosts and set resolv.conf to:
hostresorder local bind
so that it will look in /etc/hosts first before wandering off to query
the DNS servers. The hostnames in /etc/hosts do not need to be
anything real. I just have a big file with about 255 lines that looks
like:
192.168.111.1 sloth sloth.your_domain.com
192.168.111.2 pride pride.your_domain.com
192.168.111.3 glutton glutton.your_domain.com
192.168.111.4 m004
192.168.111.5 m005
192.168.111.6 m006
(...) (...)
192.168.111.253 m253
192.168.111.254 m254
The first three are real machines. The rest are place holders that
are edited as I add machines.
Also, 3.2v4.2 thru 3.2v5.0.6 allow for 3ea nameserver lines in
resolv.conf. Since you do not have a local backup nameserver, I
suggest pointing the backup nameservers to your ISP's nameservers.
Jean-Pierre Radley
| If your DNS server is sometimes down, you could put the name/IP
| translations for your machines into /etc/hosts and use "hostresorder
| local bind". I forget what the equivalent statement is for SCO Unix
| 3.2v4.2, but there was a way to get it to check /etc/hosts before DNS.
I'm looking at my 3.2v4.2 machine, and /etc/resolv.conf contains the
same 'hostresorder locl bind' as we use on later OSes.
--
JP
Andrzej Pinczuk
Thanks for all suggestions for all.
I was follow the problem, I corrected some small mistakes I made
and I found that _only_ sco 3.2 has a problem with ping by IP
when machine with DNS serves is shutdowned. Other hosts
(with sco 5.0.5) work correctly now.
After few days of fight I didn't find the solution of this problem for sco 3.2.
(I suppose that can help changing the time of waiting for dsn answering,
but I don't know where I can do it)
Sorry for my poor english :-)
Andy