topic Re: cannot telnet from server in Operating System - HP-UX

cannot telnet from server

Ian McClement_1 — Fri, 23 Aug 2002 11:21:54 GMT

Hi
I'm not sure if we have "done" something but for some reason we cannot telnet from our Unix server.
I can telnet from PC on same network to the same destination OK, leading me to think the problem is on the server itself.
We have tried rebooting (as it needed one anyway) no joy, /etc/hosts file looks OK....
Can anyone point us in the right direction where to statrt looking ?

Cheers
Ian

Re: cannot telnet from server

Jean-Luc Oudart — Fri, 23 Aug 2002 11:24:39 GMT

Have you checked inetd.sec ?
you may not be allowed to telnet from your server.

Jean-Luc

Re: cannot telnet from server

Tom Jackson — Fri, 23 Aug 2002 11:25:48 GMT

Ian:

Can you ping the the remote location?

Are your routing tables corrupt? Look at netstat -r make sure you have a default route to a gateway or a static rout to the host you are trying to connect to.

Can you ping the gateway?

hth Tom

Re: cannot telnet from server

harry d brown jr — Fri, 23 Aug 2002 11:30:23 GMT

Sorry, inetd.sec isn't going to affect telnet when telneting off of a server.

From the server can you ping the destination server?

What about the network rules one the destination server? I know you said that PC's on the "same" network work, but are the PC's and servers on the same subnet with the same network mask???

What is the error message you get when telneting to the destination server?

Have you tried TELNET'ing with the IP and NOT the destination HOST name???

live free or die
harry

Re: cannot telnet from server

Jean-Luc Oudart — Fri, 23 Aug 2002 11:43:58 GMT

Harry,

this is the inetd.sec on the target machine of course.
Jean-Luc

Re: cannot telnet from server

harry d brown jr — Fri, 23 Aug 2002 11:46:45 GMT

Sorry Jean-Luc, I put the two sentences together:

Have you checked inetd.sec ? you may not be allowed to telnet from your server.

Which is why I said the FROM server's telnet doesn't use inetd.sec.

BUT yes, you are very right, that the destination host does have to be checked, especially inetd.sec if it is a unix host.

live free or die
harry

Re: cannot telnet from server

Ian McClement_1 — Fri, 23 Aug 2002 12:15:01 GMT

OK - further info........
PC ip add=20.9.97.107
Server =20.9.97.249
def gateways same for both=20.9.97.254
netmasks same 255.255.255.0
can ping all from PC, but cannot ping 20.9.97.254 from Server.

Does this sound like a cabling problem ?

Re: cannot telnet from server

Sean OB_1 — Fri, 23 Aug 2002 12:59:54 GMT

What kind of error are you seeing?

Can you telnet into your server?

Check inetd.conf and /etc/services to verify that all are correct.

Can you nslookup the destination with FQDN and just server name?

Can you nslookup the server with FQDN and just server name?

Does reverse lookup on the the IPS of both return the correct names?

Re: cannot telnet from server

harry d brown jr — Fri, 23 Aug 2002 13:23:13 GMT

Does this sound like a cabling problem ?

NOT Necessarily.

Can you provide (for server)

(1) /etc/rc.config.d/netconf file??

(2) netstat -rn ??

(3) lanscan ??

(4) ping localhost

live free or die
harry

Re: cannot telnet from server

Sanjay_6 — Fri, 23 Aug 2002 13:32:15 GMT

Hi,

If you are using the hostname when doing a telnet from the server, are you able to ping that hostname. Can you telnet from that server as root. What if you try the telnet using the ip address. Can you ping this server from another server. inetd.sec will not effect the telnet from the server. It only affects the telnet to this server.

Do you have world read permission for the /etc/hosts file.

Hope this helps.

Regds

Re: cannot telnet from server

James Beamish-White — Fri, 23 Aug 2002 14:11:35 GMT

Hiya,

Have you tried other services? e.g. ftp? You might want to try traceroute as well and see if that works.

Is it possible that someone has put router ACLs or a firewall in between your host and the destination without telling you? They might have monitored your PC telnet so allowed it through, and not got the unix one.

Cheers!
James

Re: cannot telnet from server

James Beamish-White — Fri, 23 Aug 2002 14:17:45 GMT

Can you telnet TO the server, from the PC on the same network? If yes, I would say that it is not a cabling problem.

Can you telnet localhost from the server? If yes, then it would not be a telnet binary problem.

You may not be able to ping a gateway dependent on the gateways configuration. Does the gateway respond to a ping from the PC? If not, then you may need to change a ndd setting for ip_ire_gw_probe from 1 to 0 to allow the network to come up. If you do ifconfig lan0 does it show it is UP?

Cheers!
James

Re: cannot telnet from server

Bruce Hoffmann_1 — Sat, 24 Aug 2002 07:53:03 GMT

Ian,
If your server cannot see the default router (gateway), can it see any other hosts on it's subnet? Try to ping the subnet:
# ping 20.9.97.255
Look for a response from any IP address. If you're not getting any responses, I would say your network config is amiss. Please check the item that Harry is asking about.
Hope this helps,
Bruce

Re: cannot telnet from server

Ian McClement_1 — Mon, 26 Aug 2002 08:52:53 GMT

OK.......I hoped network team may have fixed over weekend but no
find below output from various commands..

rurprd >more /etc/rc.config.d/netconf|grep -v ^#
HOSTNAME="coirdub3"
OPERATING_SYSTEM=HP-UX
LOOPBACK_ADDRESS=127.0.0.1
INTERFACE_NAME[0]=lan1
IP_ADDRESS[0]=20.9.97.249
SUBNET_MASK[0]=255.255.255.0
BROADCAST_ADDRESS[0]=20.9.97.255
LANCONFIG_ARGS[0]="ieee"
ROUTE_DESTINATION[0]=""
ROUTE_MASK[0]=""
ROUTE_GATEWAY[0]=""
ROUTE_COUNT[0]=""
ROUTE_ARGS[0]=""
GATED=0
GATED_ARGS=""
RDPD=0
IP_ADDRESS[1]=20.9.97.249
SUBNET_MASK[1]=255.255.255.0
INTERFACE_NAME[1]=lan1
BROADCAST_ADDRESS[1]=20.9.97.255
LANCONFIG_ARGS[1]=""
ROUTE_DESTINATION[1]="default"
ROUTE_MASK[1]=""
ROUTE_GATEWAY[1]=20.9.97.254
ROUTE_COUNT[1]=1
ROUTE_DESTINATION[2]="default"
ROUTE_MASK[2]=""
ROUTE_GATEWAY[2]=20.9.97.254
ROUTE_COUNT[2]=1

rurprd >netstat -rn
Routing tables
Destination Gateway Flags Refs Use Interface Pmtu PmtuTime
20.9.97.249 127.0.0.1 UH 10 54117 lo0 4608
127.0.0.1 127.0.0.1 UH 4 1297 lo0 4608
default 20.9.97.254 UG 0 467 lan1 4170
20.9.97.0 20.9.97.249 U 7 27669 lan1 4170

Hardware Station Crd Hardware Net-Interface NM MAC HP DLPI Mjr
Path Address In# State NameUnit State ID Type Support Num
10/4/8 0x1000904B8090 1 UP lan1 UP 4 802.5 Yes 103
10/12/6 0x080009DA488C 0 UP lan0 DOWN 5 ETHER Yes 52

(not sure how the formatting of above will work)
ping localhost is fine...
ping 20.9.97.255 pings everyone except ...254
telnet localhost OK...
Can ping gateway from PC...

/> ifconfig lan0
lan0: flags=862
inet 0.0.0.0 netmask ff000000
/> ifconfig lan1
lan1: flags=863
inet 20.9.97.249 netmask ffffff00 broadcast 20.9.97.255

I hope the above answers all questions.

I am pretty sure it is not a problem on the server now - Is there some way I can say for definite so can make our network team look harder ??
Any help/pointers greatly appreciated as this is getting annoying now !!

Cheers
Ian

Re: cannot telnet from server

Steffen Jaiser — Mon, 26 Aug 2002 09:10:28 GMT

Hi,
I would say your netconf file is wrong.
INTERFACE_NAME[0]=lan1
INTERFACE_NAME[1]=lan1
which means you assign one networkcard 2 configurations.

Perhaps that's the reason?

Re: cannot telnet from server

Ian McClement_1 — Mon, 26 Aug 2002 09:59:44 GMT

Possibly
but the file has not been changed for 2 years, and prob only started friday.
Basically the problem can be narrowed down to:
Cannot see default gateway, but can see rest of network.

Re: cannot telnet from server

T G Manikandan — Mon, 26 Aug 2002 10:12:57 GMT

I had a similar problem sometime back.

My local LAN had the ip-address of the server duplicated which made me make no connections to the server.

Ping everything was fine.Local host telnet was fine.
check whether you have ip-address duplicated.

Also you have a wrong netconf file.

You are pointing to the same interface card for both the card configuration.

you have duplicated lot of entries.

If you don't have a duplicated ip-address

Just do a
/sbin/init.d/net stop

and do a fresh

/sbin/set_parms initial

to re-configure the network.
Then you can put them inside the netconf file.
(just to check if that file is the problem)

THanks

Re: cannot telnet from server

harry d brown jr — Mon, 26 Aug 2002 12:04:36 GMT

change your netconf file to look like this, because the file has a lot of mistakes in it!!! That's why I HATE set_parms --> because it toasts your netconf file!!

HOSTNAME="coirdub3"
OPERATING_SYSTEM=HP-UX
LOOPBACK_ADDRESS=127.0.0.1
INTERFACE_NAME[0]=lan1
IP_ADDRESS[0]=20.9.97.249
SUBNET_MASK[0]=255.255.255.0
BROADCAST_ADDRESS[0]=""
INTERFACE_STATE[0]=""
DHCP_ENABLE[0]=0
ROUTE_DESTINATION[0]="default"
ROUTE_MASK[0]=""
ROUTE_GATEWAY[0]="20.9.97.254"
ROUTE_COUNT[0]="1"
ROUTE_ARGS[0]=""
GATED=0
GATED_ARGS=""
RDPD=0
RARP=0

Get RID of the other crap. And I would, WITH OUT A DOUBT ---> REBOOT.

ALSO CHECK /etc/hosts, because I bet it's toast also!

live free or die
harry

Re: cannot telnet from server

Ian McClement_1 — Mon, 26 Aug 2002 12:22:51 GMT

Thanks for ideas.
I have already rebooted the server,
am gonna get the gateway (router) rebooted overnight.
If problem still there in morning then may look at "correcting" config files, but have been running with said file for 2 years, and am very wary of messing.....
Thanks again for suggestions
I will post again in morning with update.