Whats Goin' on with my web connection...

[TonyTheAutomationGuy]

I've connected my box to an existing windows network which uses a Linksys BEFSR41 broadband router for internet access. I believe all the basics are ok because I can ping to any box on the lan, the router and external hosts by FQN. So I must be hitting the router and DNS server ok. I cannot however get any web pages to load. Any time I try to browse to a web page, it times out. (Doesn't matter which browser I try)

One strange thing I noticed is that ifconfig reports my MAC as FF:FF:FF:FF:FF:FF. That's gotta be bogus, right. Bcast is reported as 192.168.0.255, I seem to recall reading somewhere that this address can be troublesome in a windows environment, I can't remember the specifics though. Anyone have some ideas? Your help is appreciated.

[Wolff]

Damn .. you got the same problem I have..
i can load webpages ending with .no or .dk or other pages very close to me, but pages abroad .. no chance in hell.
I can however, like you, ping everything, and I do, like you, use 192.168.0.* ip's.
Read my post "incredibly slow connection".
Maybe I will try another ip ...
If you fix this .. PLEASE let me know :)

[x]

This seems to be a difficult problem, don't know if I can help you but I'll try.
Tonyetc.. could have a problem with the gateway, but then it could be something else...
Could both of you please apply the output from 'ifconfig', with primary + secondary DNS-server adress.
Also check the IP-adress on the other computers, should be different but same network.
Details about your networks layout is also good.
Give me all info you can and I'll see what I can do.

[TonyTheAutomationGuy]

Thhanks for the quick reply. I'm not at the machine in question but I'll give the specifics as best as I can recall. The output from from ifconfig config seems ok. It goes something like: ip:192.168.0.199 netmask: 255.255.255.0 bcast: 192.168.0.255. the #1 and #2 DNS are reported correctly as 12.145.172.2 & .3. I am able to ping any machine on my network by IP address including my router ( lan & wan sides ). I can also ping by domain name such as yahoo.com, tech4.com etc. This leads me to believe that the network settings are correct since both internal and external hosts can be resolved. I cannot however punch a url into a browser and get a web page to load. Pretty weird, eh? It's gotta be something strangely simple since everything works...almost. BTW, I've got a 6-pack of Leinenkugels Creamy Dark for whoever posts a solution to this one! (if you're of legal age that is!) :cool:

Thanks again, Tony

[jumpedintothefire]

Found this at:
http://www.tldp.org/HOWTO/DSL-HOWTO/tuning.html#AEN692


Some Web pages won't load. For PPPoX users, the MTU value could be too high. This will cause packet fragmentation, and likely will cause misbehaving routers to fail to route your requests per Path MTU Discovery specs.The correct ppp0 device setting should be a maximum of 1492, but actually it needs to be 8 bytes less than any router you pass through on the way to the site. If a router somewhere is misconfigured, you could have problems. Try experimenting with lower MTU values. Any LAN hosts behind the connection, may even need to be even lower -- 1452 or maybe even 1412.

If ECN is enabled, it might also cause this problem. Cured with "echo 0 > /proc/sys/net/ipv4/tcp_ecn".


There is an iptable setting that could help:

iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu


found on www.shorewall.net: (http://www.shorewall.net:)

This parameter enables the TCP Clamp MSS to PMTU feature of Netfilter and is usually required when your internet connection is through PPPoE or PPTP. If set to "Yes" or "yes", the feature is enabled. If left blank or set to "No" or "no", the feature is not enabled. Note: This option requires CONFIG_IP_NF_TARGET_TCPMSS in your kernel.

[Wolff]

TTTTTTTTTNXX!! I did it !

The default MTU setting for adsl here is 1492, and the default in linux is 1500.

I just set the MTU value with

ifconfig eth0 mtu 1452

That set the mtu value to 1452 .. and what do you know .. it worked :D

[DMR]

Originally posted by TonyTheAutomationGuy:
<STRONG>One strange thing I noticed is that ifconfig reports my MAC as FF:FF:FF:FF:FF:FF. That's gotta be bogus, right.</STRONG>You IP, netmask, and broadcast address look good, but that MAC address is almost certainly bogus. Try this: unplug the machine from the network and total power down the machine, leaving it off for a few minutes. While still disconnect from the network, bring the machine back up and see if you still get the same MAC address.

Also, is the Linksys "spoofing" the MAC address of the Windows machine? Many ISP identify your connection according to the unique MAC address of your NIC, and you might have an issue related to this. If the Linksys isn't spoofing a MAC address, you might have to power down your box, cable modem (and possibly the router) for a while and then repower and reconnect to your ISP. This will allow the modem to "learn" the MAC of the newly-attached machine. With the router between your LAN and your modem, this probably isn't the case, but it's about all that I can think of...

[TonyTheAutomationGuy]

Hey, thanks to all who replied to help me out. I've resolved the issue, in a fashion, the fix is a bit embarrassing...but I'll pass it on in appreciation of y'alls assistance. I was working a netrwork problem in my office on friday (windows world) and and had to replace a NIC in an old CAD machine. It occured to me that the only reason I hadn't tried a new NIC in the Linux box is because I don't really know jack about adding and removing hardware in a Linux environment.. So what the hell, I put a $15 NetGear card in, and in ~15 minutes I had web access, had Samba running and Apache serving up web pages. DUH!! I really don't know if the integrated NIC is bad or not. It's a Microstar MB with a RTL8139 NIC chip. The machine is brand new, and I downloaded and built the latest driver as well. Still no luck. I've disabled the chip for the time being, but I'd still like to prove-out whether it's good or bad. Any other ideas?

BTW the Net gear card is running with a generic chipset based driver 'cuz I couldn't get supplied make file to work. Go figure:rolleyes:

[Lorithar]

Ahhhhhh ....

There are *two* drivers out there for the 8139 nic chips. One works on *most* the other works on the rest. ...
This may indeed have been the problem with your connection ... dunno *why* you were able to ping *anything* at all though ... makes no sense to me ...