Network computer name problem w/ Tiger and DRb

Jim Freeze · Nov 10, 2005

Hi

While running DRb, I noticed that a timeout was occuring with the URI
provided by DRb.uri. On my powerbook, DRb returned as the URI:

druby://<computer_name>.local

ort

Executing the first remote call within DRb took over a minute on
my powerbook, but was instantaneous on my sun box.

When I changed <computer_name> to <ip.ad.re.ss>, the delay
issue disappeared.

Thinking it may be a configuration issue, I fiddled with

Socket.do_not_reverse_lookup =3D true

but did not had any luck.

This is disconcerting since I had hoped that DRb.uri would return a
good address.

Does anyone know what the problem is here?

Thanks

Eric Hodel · Nov 10, 2005

While running DRb, I noticed that a timeout was occuring with the URI
provided by DRb.uri. On my powerbook, DRb returned as the URI:

druby://<computer_name>.localort

Executing the first remote call within DRb took over a minute on
my powerbook, but was instantaneous on my sun box.

Sounds like your DNS is not completely configured.

When I changed <computer_name> to <ip.ad.re.ss>, the delay
issue disappeared.

This is disconcerting since I had hoped that DRb.uri would return a
good address.

Does anyone know what the problem is here?

From the sun, what does `host ip.ad.re.ss` (or dig or nslookup)
where ip.ad.re.ss is the address of the powerbook return?

If you don't have matching forward and reverse DNS, DRb won't be able
to return a good hostname.

Kirk Haines · Nov 10, 2005

When I changed <computer_name> to <ip.ad.re.ss>, the delay
issue disappeared.

Thinking it may be a configuration issue, I fiddled with

Socket.do_not_reverse_lookup = true

This sounds like a simple DNS lookup issue with computer_name.

That'd be the first place I would investigate, anyway.

Kirk Haines

Jim Freeze · Nov 10, 2005

Sounds like your DNS is not completely configured.

The PowerBook DNS? BTW, I am attaching to my company network.

From the sun, what does `host ip.ad.re.ss` (or dig or nslookup)
where ip.ad.re.ss is the address of the powerbook return?

It says:

% host /jim-freezes-powerbook-g4-15.local
Host /jim-freezes-powerbook-g4-15.local not found: 3(NXDOMAIN)

But DRb still works, it just has to wait for a timeout for the first
remote call.
All subsequent calls are fast.

If you don't have matching forward and reverse DNS, DRb won't be able
to return a good hostname.

Since the computer connects with DHCP to the network, adding host entry
won't help here. And, I don't think I should have to run bind on my
laptop to get this to work.

Any suggestions?

Jim Freeze · Nov 10, 2005

BTW, host failed, but dig seems to work:

% dig 'jim-freezes-powerbook-g4-15.local'

; <<>> DiG 9.2.2 <<>> jim-freezes-powerbook-g4-15.local
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 50543
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;jim-freezes-powerbook-g4-15.local. IN A

;; AUTHORITY SECTION:
539 IN SOA frootb.mycompany.net.
dnssupport.mycompany.com. 2004059055 14400 3600 604800 600

;; Query time: 66 msec
;; SERVER: 10.208.0.3#53(10.208.0.3)
;; WHEN: Thu Nov 10 17:00:07 2005
;; MSG SIZE rcvd: 130

Guillaume Marcais · Nov 10, 2005

BTW, host failed, but dig seems to work:

No, this dig output shows that there is no answers to your query. So the
look up failed.

% dig 'jim-freezes-powerbook-g4-15.local'

; <<>> DiG 9.2.2 <<>> jim-freezes-powerbook-g4-15.local
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 50543
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ^^^^^^^^^^^^^^^^^^^

;; QUESTION SECTION:
;jim-freezes-powerbook-g4-15.local. IN A

This is your question/query.

No ANSWER SECTION.

HTH,
Guillaume.

Eric Hodel · Nov 10, 2005

The PowerBook DNS? BTW, I am attaching to my company network.

It says:

% host /jim-freezes-powerbook-g4-15.local
Host /jim-freezes-powerbook-g4-15.local not found: 3(NXDOMAIN)

A failure with your IP address is more informative. I wouldn't
expect every DHCP server to properly update DNS when it hands out
leases.

But DRb still works, it just has to wait for a timeout for the first
remote call.
All subsequent calls are fast.

Right, DRb does an RDNS lookup to figure out the local host name,
which probably takes forever.

Since the computer connects with DHCP to the network, adding host
entry
won't help here. And, I don't think I should have to run bind on my
laptop to get this to work.

Any suggestions?

The DHCP address you're handed should have matching forward and
reverse DNS. Complain to your network admins.

Eric Hodel · Nov 10, 2005

BTW, host failed, but dig seems to work:

% dig 'jim-freezes-powerbook-g4-15.local'

; <<>> DiG 9.2.2 <<>> jim-freezes-powerbook-g4-15.local
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 50543
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

^^^^^^^^^

ANSWER would be 1 if it found a matching record.

Guillaume Marcais · Nov 10, 2005

Since the computer connects with DHCP to the network, adding host entry
won't help here. And, I don't think I should have to run bind on my
laptop to get this to work.

Not on your laptop. But your DHCP server and you DNS server should
probably talk to each other so that:

1) your laptop gets a meaningful domain name (I doubt 'local' is it)
2) have the DNS server know about the IP given away by the DHCP server.

If you are using dhcpd by isc.org, lookup the 'DYNAMIC DNS UPDATES'
paragraph in the dhcpd.conf(5) man page.

Guillaume.

Jim Freeze · Nov 10, 2005

Right, DRb does an RDNS lookup to figure out the local host name,
which probably takes forever.

What is RDNS. Is there a command line version of this so I can
see it work?

The DHCP address you're handed should have matching forward and
reverse DNS. Complain to your network admins.

Yes. I will. Is there a commandline app that will show that a matching
reverse DNS is not being provided? Or just a dig failure?

Yohanes Santoso · Nov 11, 2005

Jim Freeze said:
What is RDNS. Is there a command line version of this so I can
see it work?

reverse dns.

$ dig -x 68.142.226.47

; <<>> DiG 9.2.4 <<>> -x 68.142.226.47
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 943
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;47.226.142.68.in-addr.arpa. IN PTR

;; ANSWER SECTION:
47.226.142.68.in-addr.arpa. 1200 IN PTR p16.www.re2.yahoo.com.

;; Query time: 154 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Nov 10 19:39:59 2005
;; MSG SIZE rcvd: 79

$ dig p16.www.re2.yahoo.com.

; <<>> DiG 9.2.4 <<>> p16.www.re2.yahoo.com.
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50006
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;p16.www.re2.yahoo.com. IN A

;; ANSWER SECTION:
p16.www.re2.yahoo.com. 1800 IN A 68.142.226.47

;; Query time: 158 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Nov 10 19:40:07 2005
;; MSG SIZE rcvd: 55

YS

Eric Hodel · Nov 11, 2005

What is RDNS. Is there a command line version of this so I can
see it work?

Reverse DNS. You do a RDNS lookup when you look up by IP instead of
by name:

$ ifconfig fxp0 | grep inet
inet 192.168.1.13 netmask 0xffffff00 broadcast 192.168.1.255
inet6 fe80::208:2ff:febb:cd4c%fxp0 prefixlen 64 scopeid 0x1

Reverse:

$ host 192.168.1.13
13.1.168.192.in-addr.arpa domain name pointer RUR-3.coop.robotcoop.com.

Forward:

$ host rur-3.coop.robotcoop.com
rur-3.coop.robotcoop.com has address 192.168.1.13

Yes. I will. Is there a commandline app that will show that a matching
reverse DNS is not being provided? Or just a dig failure?

$ host `ifconfig | grep 'inet ' | grep -v '127' | cut -d ' ' -f 2`
70.1.168.192.in-addr.arpa domain name pointer kaa.coop.robotcoop.com.

Should do it for BSDlike systems like your Mac.

x1 · Nov 11, 2005

I also found some weird stuff with DRb & uri..

In specific, the receiving server would not yield data to the client
if the clients primary dns suffix was not dns-able.... In my opinion,
I would htink the server would attempt to validate or dns the client
via wins or lm/hosts but.. dunno..

My article here:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/157389?help-en

good luck

Jim Freeze · Nov 11, 2005

On Nov 10, 2005, at 3:29 PM, Jim Freeze wrote:
$ host `ifconfig | grep 'inet ' | grep -v '127' | cut -d ' ' -f 2`
70.1.168.192.in-addr.arpa domain name pointer kaa.coop.robotcoop.com.

Thanks for all the good info, but I am still confused as to how
drb client utlimately got the ip address of the server machine when
it is impossible to do from the commandline.

x1 · Nov 11, 2005

Netbios? Can you ping the hostname?

Thanks for all the good info, but I am still confused as to how
drb client utlimately got the ip address of the server machine when
it is impossible to do from the commandline.

Jim Freeze · Nov 11, 2005

Netbios? Can you ping the hostname?

# From Sun box
% ping JDFPBook
ping: unknown host JDFPBook

# From PowerBook
% ping JDFPBook
ping: cannot resolve JDFPBook: Unknown host

Eric Hodel · Nov 11, 2005

Thanks for all the good info, but I am still confused as to how
drb client utlimately got the ip address of the server machine when
it is impossible to do from the commandline.

I don't have a clear-enough picture of your environment to answer
this for you.

I'd need to know which machine is the server, which is the client,
the forward and reverse DNS for each machine, and an output of the
failure.

x1 · Nov 11, 2005

Tell me the IP & submet mask of both machines..

my guess is that they're not in the same subnet...

Network computer name problem w/ Tiger and DRb

Jim Freeze

Eric Hodel

Kirk Haines

Jim Freeze

Jim Freeze

Guillaume Marcais

Eric Hodel

Eric Hodel

Guillaume Marcais

Jim Freeze

Yohanes Santoso

Eric Hodel

x1

Jim Freeze

x1

Jim Freeze

Eric Hodel

x1

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