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Old 10-30-2004, 11:15 AM   #1
djkadu
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Registered: Oct 2004
Location: London
Distribution: Debian woody
Posts: 4

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Gateway works fine but i can't ping from it.


Hi, I'm using a debian woody box as my gateway at home, It has a network card for the local network (eth0) and a internal ADSL card for the internet connection (ppp0)

Everything was forking fine for the 2 years untill a few months ago someting happend.
The gateway still working fine and I can full access to the internet from any computer on the network, except fom it. I mean, if I log in to it (SSH2) I can't PING anything, on the local network or on the internet, even using the IP addreses.
i'm not an expert in linux, but i've been using it for a few years. I think is something related to the routes, but I don't know nothing about it.
So here is the output of my route command:

xavier:~# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
62.241.161.247 * 255.255.255.255 UH 0 0 0 ppp0
localnet * 255.255.255.0 U 0 0 0 eth0
default 62.241.161.247 0.0.0.0 UG 0 0 0 ppp0

and this is my ifconfig:

xavier:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:E0:18:20:06:93
inet addr:192.168.100.100 Bcast:192.168.100.255 Mask:255.255.255.0
inet6 addr: fe80::2e0:18ff:fe20:693/10 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:124706398 errors:0 dropped:0 overruns:0 frame:0
TX packets:132292627 errors:3 dropped:0 overruns:0 carrier:3
collisions:0 txqueuelen:100
RX bytes:3095407628 (2.8 GiB) TX bytes:1083118492 (1.0 GiB)
Interrupt:5 Base address:0xb800 Memory:e1800000-e1800038

imq0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
UP RUNNING NOARP MTU:1500 Metric:1
RX packets:137482763 errors:0 dropped:0 overruns:0 frame:0
TX packets:137482763 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:30
RX bytes:2751651323 (2.5 GiB) TX bytes:2751651323 (2.5 GiB)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:356 errors:0 dropped:0 overruns:0 frame:0
TX packets:356 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:23354 (22.8 KiB) TX bytes:23354 (22.8 KiB)

ppp0 Link encap:Point-to-Point Protocol
inet addr:*.*.*.* P-t-P:62.241.161.247 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1300 Metric:1
RX packets:69850422 errors:0 dropped:0 overruns:0 frame:0
TX packets:63021821 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:60
RX bytes:3496095464 (3.2 GiB) TX bytes:4061874683 (3.7 GiB)

the imq0 is there becous I use a network shaper script for the ADSL connection.

Well, if you need any more information please ask, Any help is very appreciated.
thanks
Kadu
 
Old 10-30-2004, 11:30 AM   #2
Mara
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Registered: Feb 2002
Location: Grenoble
Distribution: Debian
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Routing table looks OK. It may be something with firewall (you have NAT/masquerade, I think) or the shaper.
 
Old 10-30-2004, 02:59 PM   #3
djkadu
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Registered: Oct 2004
Location: London
Distribution: Debian woody
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OK, that's a beggining.
I already deactivated the script and i'm using iptables i beleive

xavier:~# iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
UNCLEAN all -- anywhere anywhere unclean
ACCEPT all -- anywhere anywhere
LD all -- anywhere anywhere state INVALID
ACCEPT all -- localnet/24 anywhere
LD all -- 224.0.0.0/8 anywhere
LD all -- anywhere 224.0.0.0/8
LD all -- 255.255.255.255 anywhere
LD all -- anywhere 0.0.0.0
LD all -- anywhere anywhere state INVALID
ACCEPT tcp -- anywhere anywhere tcp dpts:bootps:bootpc
ACCEPT udp -- anywhere anywhere udp dpts:bootps:bootpc
ACCEPT tcp -- anywhere anywhere tcp dpts:netbios-ns:netbios-ssn
ACCEPT udp -- anywhere anywhere udp dpts:netbios-ns:netbios-ssn
ACCEPT tcp -- anywhere anywhere tcp dpt:445
ACCEPT udp -- anywhere anywhere udp dpt:445
ACCEPT tcp -- anywhere anywhere tcp dpt:2049
ACCEPT udp -- anywhere anywhere udp dpt:2049
LD tcp -- anywhere anywhere tcp dpts:x11:6015
LD udp -- anywhere anywhere udp dpts:x11:6015
ACCEPT tcp -- anywhere anywhere tcp dpts:bootps:bootpc
ACCEPT udp -- anywhere anywhere udp dpts:bootps:bootpc
LD tcp -- anywhere anywhere tcp dpt:5000
LD udp -- anywhere anywhere udp dpt:5000
LD tcp -- anywhere anywhere tcp flags:!SYN,RST,ACK/SYN state NEW
ACCEPT tcp -- anywhere anywhere tcp spt:ssh dpts:login:65535 flags:!SYN,RST,ACK/SYN state RELATED
ACCEPT tcp -- anywhere anywhere tcp spt:ftp-data dpts:1023:65535 flags:!SYN,RST,ACK/SYN state RELATED
LD all -- anywhere anywhere
ACCEPT udp -- anywhere anywhere udp dpt:6699
ACCEPT udp -- anywhere anywhere udp dpt:6699
ACCEPT tcp -- anywhere anywhere tcp dpt:6699

Chain FORWARD (policy DROP)
target prot opt source destination
UNCLEAN all -- anywhere anywhere unclean
ACCEPT tcp -- anywhere 192.168.100.110 tcp dpt:3389
ACCEPT all -- localnet/24 anywhere
ACCEPT all -- anywhere localnet/24

Chain OUTPUT (policy DROP)
target prot opt source destination
UNCLEAN all -- anywhere anywhere unclean
ACCEPT all -- anywhere anywhere
ACCEPT all -- localnet/24 anywhere
ACCEPT icmp -- localnet/24 anywhere
LD all -- 224.0.0.0/8 anywhere
LD all -- anywhere 224.0.0.0/8
LD all -- 255.255.255.255 anywhere
LD all -- anywhere 0.0.0.0
DROP tcp -- anywhere anywhere tcp flags:!SYN,RST,ACK/SYN state NEW
all -- anywhere anywhere TTL match TTL == 64
ACCEPT all -- anywhere anywhere
ACCEPT udp -- anywhere anywhere udp spt:6699
ACCEPT udp -- anywhere anywhere udp spt:6699
ACCEPT tcp -- anywhere anywhere tcp dpt:6699

Chain LD (19 references)
target prot opt source destination
LOG all -- anywhere anywhere LOG level warning
DROP all -- anywhere anywhere

Chain SANITY (0 references)
target prot opt source destination
LD all -- anywhere anywhere

Chain STATE (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere state NEW
LD all -- anywhere anywhere

Chain UNCLEAN (3 references)
target prot opt source destination
LD all -- anywhere anywhere
 
Old 10-31-2004, 09:49 AM   #4
Mara
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Registered: Feb 2002
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Distribution: Debian
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Iptables, definitely Unfortunately I have problems reading the output (iptables -L). I'm interested in the part of the script dealing with OUTPUT chain. If it's not too long, please copy it.
 
Old 10-31-2004, 12:31 PM   #5
ugge
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Registered: Dec 2000
Location: Gothenburg, SWEDEN
Distribution: OpenSUSE 10.3
Posts: 1,028

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According to this listing it seems as though your firewall lets just about anything through, except for malformed packets.
To have a closer look at the fancy settings it would nice with a listing from
Code:
iptables -n -v -L
 
  


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