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linux juggler 12-09-2004 03:18 AM

i can connect to the internet but i cant ping ??
hello every one .. i hope that you are fine ...

i have installed FC3 but i cant ping any things ...
my fire fox work fine ...

but when ever i try to ping any things it says :
[root@lfs ~]# ping
PING ( 56(84) bytes of data.
From icmp_seq=0 Dest Unreachable, Bad Code: 9
From icmp_seq=1 Dest Unreachable, Bad Code: 9
From icmp_seq=2 Dest Unreachable, Bad Code: 9
any one have any idea ??
how can i solve this problem ?
my Kopete also don't work .... maybe for the same reason ....

thank you :Pengy: :Pengy:

jschiwal 12-09-2004 04:02 AM

If you are trying to ping another computer on the local network, make sure that that computer is running a ping service and that the firewalls are not blocking pings. Sometimes the ping service isn't enabled to help hide the IP address from hackers, and to avoid the POD (ping of death) attacks.

You also want to make sure that the other computers on your LAN are using the same subnet. The destination host unreachable indicates that this isn't the case. The address you are trying to ping (192.168.XXX.XXX) is a private address. A router will not forward traffic that uses such an address.

You need to provide more information on your network. How do you connect to the Internet, and how do you connect to the your local network. Do you have a cable/asdl router that performs NAT translation for each computer on the local network, or do you have a dial-up modem to the Internet and an Ethernet card for the local network?

What is the output of the /sbin/ifconfig and /sbin/route commands?

linux juggler 12-09-2004 07:15 AM

first i want to thank you :
second i didnt ping any computer in my lan coz am using a standalone computer ....
3ed the result of the " ifconfig " is
eth0 Link encap:Ethernet HWaddr 00:30:0A:00:2B:9D
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:10 Base address:0xcc00

lo Link encap:Local Loopback
inet addr: Mask:
RX packets:1537 errors:0 dropped:0 overruns:0 frame:0
TX packets:1537 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2255101 (2.1 MiB) TX bytes:2255101 (2.1 MiB)

ppp0 Link encap:Point-to-Point Protocol
inet addr: P-t-P: Mask:
RX packets:1434 errors:0 dropped:0 overruns:0 frame:0
TX packets:1437 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:945160 (923.0 KiB) TX bytes:198500 (193.8 KiB)

and the ouput of the " route " is :
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface * UH 0 0 0 ppp0
default UG 0 0 0 ppp0

right now am using the kppp to connect to my ISP ...

rhoekstra 12-09-2004 08:27 AM

You're connecting to your work? because you don't get an IP which is publicly available...

You can ping localhost? (, just to make sure 'ping' is okay... (hey, let's start at the start :) )

can you ping your peer?

How does get resolved?
does 'host' bring you a good result? This would mean that DNS resolving _is_ working.. (probably, because you also said that FireFox is working... just trying to exclude possibilities).

@jschiwal, he wasn't trying to ping a local IP, but rather, which had ip, it is rather the peer that is reporting a problem..

Perhaps the peer is not allowing ping to go through.. I would guess this last... You can ask this at the owner of the peer system (your work? your ISP?)

It could be filtering, which would explain Kopete not working, perhaps that is filtered as well..

linux juggler 12-10-2004 06:32 AM

- yes i can ping through my
- no i cant ping my
- and the result of ' host ' is ' has address '

so you think that my ISP doesnt allow me to go through them ....

and thats why my yum didnt work also .. ?

linux juggler 12-10-2004 06:36 AM

when ever i type ' yum update check ' i got this message :
Repository updates-released already added, not adding again
Repository base already added, not adding again
Setting up Update Process
Setting up Repo: livna-stable [Errno 4] IOError: <urlopen error (101, 'Network is unreachable')>
Trying other mirror.
Cannot open/read repomd.xml file for repository: livna-stable
failure: repodata/repomd.xml from livna-stable: [Errno 256] No more mirrors to try.

dustu76 12-10-2004 06:53 AM

I have a dialup connection (for forum-members from Mumbai, India - my ISP is MTNL, Mumbai) & my experience is similar:

1. I can surf.
2. I can ftp.
3. I can ping localhost
4. I can ping my peer
5. $ host <somedomain> works fine.
3. Even yum/xmule etc. works fine.

But I cant ping any other domain. Even .edu domains (which allow ping) cannot be pinged.

I have the firewall running (using redhat-config-*), but that only shows common services like ftp, telnet etc. which I'm not running anyway.

Is it a firewall issue? Or is my ISP blocking ping (pls dont ask me to contact them 'cause their response is pathetic :(

Any other info I should post?

rhoekstra 12-10-2004 07:03 AM

You can see if your firewall is blocking on the response you get.

Alternatively, presuming that hte internet connection is dialup, so ppp0, you can do a 'tcpdump -i ppp0' to check that the ping commands leave your machine.

dustu76 12-10-2004 07:07 AM

How do I check whether my firewall is blocking pings?

I presume that by checking tcpdump, you mean after my ppp0 is up, I execute "tcpdump -i ppp0 is" in one xterm & fire the ping commands in another xterm? I'm right now not on a linux machine so just confirming?

Thanks for responding.

rhoekstra 12-10-2004 07:16 AM

Yep, open up two terminals, open your dial up connection and start 'tcpdump -i ppp0'.

This terminal shall monitor activity on the ppp0 device. (recommended to stop any service, like yum or kopete to stop noise created by other programs.., you can also filter more with tcpdump, but you want to see as much as possible, right.)

on the other terminal start a ping...

What IP do you get from your provider, a public one? or a private one? (private = 10.x.x.x, 172.16-32.x.x, 192.168.x.x).
Most ISPs provide a public IP so you are directly reachable from the internet..

About the yum error from linux juggler, perhaps yum wants to ping to make sure the server is up? by failing, it assumes the server is down.. Anyone have experience with this? This is what I would guess if every service works except ping and yum.

linux juggler 12-10-2004 07:54 AM

when i try what you said like ' tcpdump -i ppp0 '
i go this :
14:49:35.814921 IP > icmp 36: net unreachable - admin prohibited
14:49:35.854915 IP > icmp 36: net G.ROOT-SERVERS.NET unreachable - admin prohibited
which as i think that the admin of my ISP prohibited my ping so that i cant use eather yum or up2date ....

am i right ?

PS: i dont have any dhcp working or firewall ... both are disabled ....

rhoekstra 12-10-2004 08:13 AM

I assume is your 'peer', your ISP, and that is your IP...

This tells you that, indeed, the ping left your machine, and got returned by your ISP.

I wonder why your ISP would block ICMP packages... ?!?!?..

Were you doing a ping? to which hostname? because I see responses about DNS root servers??
Not sure what is happening.. If you ran yum, that would be because I am not a yum specialist. . . :)

linux juggler 12-10-2004 08:19 AM

am doing it from root user to my site

dustu76 12-10-2004 09:38 AM

Guys, here are the outputs from various commands (I'm sorry that this is slightly long but I didn't know how much & what to capture):


[/home/soumen] $ host has address
[/home/soumen] $ ping
PING ( 56(84) bytes of data.
From icmp_seq=0 Packet filtered
From icmp_seq=1 Packet filtered
From icmp_seq=2 Packet filtered
From icmp_seq=3 Packet filtered
From icmp_seq=4 Packet filtered

--- ping statistics ---
5 packets transmitted, 0 received, +5 errors, 100% packet loss, time 4049ms
, pipe 2


[/home/soumen] # /usr/sbin/tcpdump -i ppp0
tcpdump: listening on ppp0
19:57:13.935061 >  63233+ A? (29) (DF)
19:57:14.055506 >  63233 1/2/2 A (135)
19:57:14.056149 > icmp: echo request (DF)
19:57:14.175516 > icmp: host unreachable - admin prohibited filter
19:57:14.176153 >  63234+ PTR? (44) (DF)
19:57:14.305504 >  63234 NXDomain* 0/1/0 (131)
19:57:15.075579 > icmp: echo request (DF)
19:57:15.205504 > icmp: host unreachable - admin prohibited filter
19:57:16.086241 > icmp: echo request (DF)
19:57:16.195512 > icmp: host unreachable - admin prohibited filter
19:57:17.095607 > icmp: echo request (DF)
19:57:17.215504 > icmp: host unreachable - admin prohibited filter
19:57:18.105580 > icmp: echo request (DF)
19:57:18.225516 > icmp: host unreachable - admin prohibited filter

14 packets received by filter
0 packets dropped by kernel


[/home/soumen] $ /sbin/route -n
Kernel IP routing table
Destination    Gateway        Genmask        Flags Metric Ref    Use Iface UH    0      0        0 ppp0    U    0      0        0 lo      U    0      0        0 lo        UG    0      0        0 ppp0
[/home/soumen] $ /sbin/ifconfig -a
lo        Link encap:Local Loopback 
          inet addr:  Mask:
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:496 (496.0 b)  TX bytes:496 (496.0 b)

ppp0      Link encap:Point-to-Point Protocol 
          inet addr:  P-t-P:  Mask:
          RX packets:778 errors:0 dropped:0 overruns:0 frame:0
          TX packets:775 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:525487 (513.1 Kb)  TX bytes:69947 (68.3 Kb)

[/home/soumen] $ cat /etc/resolv.conf

Phew :) I already have a sneaky feeling that my problem is same as linux Juggler's.. "admin prohibited" !!

Now what ? :(

rhoekstra 12-10-2004 10:18 AM

You both have the same problems, that's for sure..

dustu76, your yum worked right? where linux juggler hasn't even got luck with yum . . .

Also, linux juggler seems to get a private IP from his ISP, while you have a public IP, thus accessible from the outside world.. so to say.

I'm afraid that in order to resolve this is to switch ISP, or (indeed) contact them and ask why in heaven they block ICMP packets...

disclaimer: I still don't know what prohibits yum to work . . . so it's not a suggestion to get that issue fixed..

Good luck, guys!

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