Wierd Mandrake Networking Problem

When I got my new Hard Disk, I decided to try out Mandrake Linux instead of my usual Slackware. The setup went like a dream, however, since I couldn't remember my DNS server addresses, I edited my resolv.conf after the install to add the following lines and remove the line that starts with domain:

Code:

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nameserver xxx.xxx.xxx.xxx
nameserver xxx.xxx.xxx.xxx

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Now, everything seemed fine with all domains being resolved. However, except for a few sites (that are hosted in my country like google.co.in or indiatimes.com), nothing loads. My ISP's router blocks ICMP echo reply, so I can't ping anything to see whether it's up. However, by pinging, I did find out that all the domains resolve. Another interesting thing is that typing google.com redirects me to google.co.in (because of google's redirecting system) but type say, antionline.com, all it does is time out. A netstat says SYN_SENT for the connections that time out and established for the ones that load (obviously). Also, the net works fine from Windows XP.

I've setup the following things (just in case I'm missing something):
IP - Static IP address 90.0.0.245
Gateway - 90.0.0.1
DNS Servers - xxx.xxx.xxx.xxx and xxx.xxx.xxx.xxx

Cheers,
cgkanchi

It is possible there have been/are networking problems with or beyond your upstream service provider.

DNS resolutions indicates you are talking to your dsn servers, and you can connect to local addresses, indicating that newtorking and TCP/IP connectivity is good.

Are you still having problems.

Try borrowing or using another machine to see if the fault is with your PC or elsewhere.

Steve

Works from windows. Doesn't work from linux. Therefore no problems with my upstream provider.
Cheers,
cgkanchi

Sorry, missed the bit in the original post about it working under windows :(

That is wierd.

I don't have much of a clue to be honest, unless the traffic is being filtered somwhere.

Do you have iptables installed & running? If so try switching it off - If everything works, that's where your problem is.

Are you really using the IP Address 90.0.0.1 and 90.0.0.254, or have you changed these to protect the innocent ;)

Are these your internal IP addresses ?

Are these the same IP addresses that windows uses?

I don't know enough about the reserved addresses but whois states:
[Querying whois.arin.net]
[whois.arin.net]

OrgName: Internet Assigned Numbers Authority
OrgID: IANA
Address: 4676 Admiralty Way, Suite 330
City: Marina del Rey
StateProv: CA
PostalCode: 90292-6695
Country: US

NetRange: 85.0.0.0 - 95.255.255.255
CIDR: 85.0.0.0/8, 86.0.0.0/7, 88.0.0.0/5
NetName: RESERVED-11
NetHandle: NET-85-0-0-0-1
Parent:
NetType: IANA Reserved
Comment:
RegDate:
Updated: 2003-11-17


Could these be having routing problems?

Just taking a stab in the dark.

Steve

My IP address is a NATted address (90.0.0.245). My ISP's gateway is 90.0.0.1 and the DNS servers are xxx.xxx.xxx.xxx and xxx.xxx.xxx.xxx (IP's hidden for obvious reasons). IPTables is up and running, however, I can't see any reason why certain sites should load and certain sites shouldn't. I'll give it a go anyways.
Cheers,
cgkanchi

Some more information...
I tried turning IPTables off. Didn't work. On a hunch, I tried as root. That didn't work either. A netstat shows

Quote:

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tcp 0 1 chinmayk.spaceage:32781 h-xxx-xxx-xxx-xxx-:http SYN_SENT

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and two more lines with TIME_WAIT as their status.

Cheers,
cgkanchi

I'm baffled.

What does your rooting table look like (route) And what is the result of a tracroute to a site you can connect to vs one you can't connect to.

And just on the off chance, the windows machine, what IP has it got and are you sure its not using cached pages for displaying the sites that don't work on the mandy box

I'm really baffled by this.

Since my ISP's router blocks ICMP Echo Reply, I can't traceroute either. And I know that it's not using cached pages because I'm posting this off it.
Cheers,
cgkanchi

I'm sure traceroute uses udp by default.

Have you looked at your routing table, cause unless that reveals something interesting, I haven't a clue.

Steve

OK, I finally solved the problem! It turns out that my ISP's firewall (GuardianPro) doesn't like Linux's implementation of TCP. For some reason, if tcp_timestamps is enabled, most sites just refuse to load. So, to set tcp_timestamps to disabled, you have to type the following command.

Quote:

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echo 0 > /proc/sys/net/ipv4/tcp_timestamps

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This seems to be an issue with GuardianPro firewall because I found another person with the same problem: http://www.experts-exchange.com/Netw..._20704833.html

Cheers,
cgkanchi

I'd have never found that - Well done!