Internet's fine but can't ping!

[Dalani]

I recently noticed that I couldn't send out emails from Evolution via either Smtp or sendmail. I used PING and traceroute to check the network and no trace or packet gets sent. Even on the localhost. Retracing my steps, I found this started occuring when I set my Linux box to activate internet connection at boot up to allow my non-root users access to the net.

I googled on this and even found this useful Network troubleshooting HOW-TO but don't know how to proceed from there. http://ubuntuforums.org/showthread.php?t=25557


So internet works, can receive emails but cannot send or ping any site local or otherwise.
Network gurus: any help would be appreciated


edit: here is a ifconfig 'snapshot'

:~$ ifconfig
ppp0      Link encap:Point-to-Point Protocol
          inet addr:216.xxx.xx.x  P-t-P:216.yyy.yy.yy  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:2097 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2257 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:1732855 (1.6 MiB)  TX bytes:367633 (359.0 KiB)

[likwid]

Sounds like something is blocking ICMP traffic. Did you configure a firewall? I am not familiar with Ubuntu, does it automatically configure firewall settings for you?

[Dalani]

Been using firestarter for quite a while configured and unchanged. I havn't modified tables. Is it possible enabling internet connection (using iface,ifup,ifdown) at startup could have modified firewall settings?????

[likwid]

Hmmm I guess there could be a way, why don't you check and see? Comment out the interface configuration commands in your rc scripts, or reverse whatever steps you took to start it at boot. See if you have the same problem.

[slimat]

check this
echo 0> /proc/....../ipv4/ig_ping _all?
(ignore ping! if the value is set to 1 ,u cant ping any sys or host)
i`m not sure abt the path and exact file to be edited (sorry)
but i think this might be u r prob!.

[Dalani]

Thanks I tweaked my firestarter firewall to allow ICMP . I can trace route but can't ping. Im not sure about ig_ping _all? it's not in my system. Can you elaborate?

[likwid]

Yes /proc/sys/net/ipv4/ is the path icmp something i believe is the file.

[Dalani]

My internet at bootup is using this internet superserver config file below. All the services are commented out. That might be why sending mail doesn't work. But then again I can recieve mail and use the internet. Are there network gurus who can elucidate this.

What is the menu item or CLI syntax to check what services are running????

#
# Internet server configuration database
#
#
# Lines starting with "#:LABEL:" or "#<off>#" should not
# be changed unless you know what you are doing!
#
# If you want to disable an entry so it isn't touched during
# package updates just comment it out with a single '#' character.
#
# Packages should modify this file by using update-inetd(8)
#
# <service_name> <sock_type> <proto> <flags> <user> <server_path> <args>
#
#:INTERNAL: Internal services
#echo        stream    tcp    nowait    root    internal
#echo        dgram    udp    wait    root    internal
#chargen    stream    tcp    nowait    root    internal
#chargen    dgram    udp    wait    root    internal
#discard    stream    tcp    nowait    root    internal
#discard    dgram    udp    wait    root    internal
#daytime    stream    tcp    nowait    root    internal
#daytime    dgram    udp    wait    root    internal
#time        stream    tcp    nowait    root    internal
#time        dgram    udp    wait    root    internal

#:STANDARD: These are standard services.

#:BSD: Shell, login, exec and talk are BSD protocols.

#:MAIL: Mail, news and uucp services.

#:INFO: Info services

#:BOOT: Tftp service is provided primarily for booting.  Most sites
# run this only on machines acting as "boot servers."

#:RPC: RPC based services

#:HAM-RADIO: amateur-radio services

#:OTHER: Other services

[likwid]

I don't think inetd.conf has much to do with this. Sendmail is started as a daemon, separate from inetd. To get a status of your 'services' try service --status-all at a command line. Though I'm not sure this command is on your system. Otherwise you would just check the output of ps.

[Dalani]

I checked the ouput of the ps --ax command at console and neither sendmail or postfix or exim is listed as running..Postfix is installed according to synaptic. So it's jsut a matter of looking into getting postfix running at bootup....