Clients can´t access some web pages from our network

[asanes]

Hi,

some of our clients can´t access certain web pages from our isp network, i´ve been looking to those pages and find out their ip addresses and all they come from a spint client acording to the ARIN db. I scaned port 80 in all the ip blocks assigned to that sprint client and i see that some of those ip address respond correctly to port 80 from our network, but, those pages with addresses in those IP blocks that can´t be accessed doesn´t respond to queries on port 80. I can´t access with the ip address on my browser, so i can conclude it isn´t a DNS problem, also, i am receiving the blocks the way sprint is announcing them on my border routers... so, i am kind of stray about the cause of this problem, i would appreciate any advise... Best Regards,

Aisha Sanes

[rjackson]

It sounds like you are saying that the client is on your ISP and the addresses they cannot reach are elsewhere on the Internet.

Can you reach the networks in question with any other protocols; ping, smtp etc.? If you can it sounds like a firewall problem, the other side is not letting port 80 through. If you cannot it may be a routing problem. The other side may not be able to find your addresses. Do you know if this works from any other ISPs? It could still be a DNS problem if you client is new and the other side is doing reverse lookups. It may take a week before they can get a good answer.

[asanes]

Hi,

The web pages do work from other ISPs.

I am trying to reach the web pages from our backbone and i can´t reach the pages so i think it isn´t a DNS problem.

The web pages has IP addresses from one block that i am learning from our border routers and i do reach some of those IP address that are also being used on that block in port 80, so, i can´t see the routing problem.

I can´t reach the addresses in cuestion from any protocol, i scaned them in many of them and i didn´t get an answer.

Hope you have an idea what may be happing,

Regards,

asanes

[edeo]

I have the same, or similar, problem. Certain websites are unreachable from within the network. Cannot ping them either. These are major websites, such as macromedia.com. I have a Cisco 800 router that is otherwise working just fine. Any suggestions would be greatly appreciated.

[asanes]

Maybe they´ve blocked your ip address block, that was happenning with us. I recommend you to discard any routing problem, first check on a looking glass the ip address of the web page you cannot reach and them check if you´re learning the route to that web site, if not, them you have a routing problem (or your service provider) otherwise you´re being block, it is normal for web sites to block pinging but you still can access them on port 80. I hope this helps

[j.stringer]

I'm sure you already know this, but, to rule out an acl block at the distant end go to you border router and telnet to the destination over port 80 ...

router#telnet www.macromedia.com 80

hope this helps