what ports do I open for internet access?

[abaseballfan]

Hi, can anyone tell me the ports I need to have opened for internet access? I have a Cisco 831 router and have about 10 open right now but there are certain sites like Yahoo sports and msn in general that do not want to open or take forever to open, and when I hook my Linksys back up it jumps right on them sites, so I have something wrong I believe with the ports? any ideas? Thanks.

 

[tygressjanie]

Port 80 is the most commonly used port for internet access. Perhaps you might want to check and see if your new router has this port closed?

 

[SimonDavies]

I would also have a look to see if ports 81 and 443 are open as well. 81 is used sometimes for http data and 443 is for https.

What ports do you have open and why? I wonder whether you have zombies going out of your machine that are working out of the new box but not the old one??

Try doing a netstat sometime to see who you are communicating with.
Netstat -a or a -n should give you some idea

 

[Serbtastic]

As far as I know, port 81 is never used for http data, only port 80. Do you have any references that indicate otherwise?

 

[SimonDavies]

I did a quick search and found this.

http://grc.com/port_81.htm

I have in the past experienced sites who operated from port81, because of that I generally open up 80,81 and 443 for http access, depending if I need ftp depends if I open 20 and 21.

 

[gurner]

you shouldn't need an outbound access list other than

access-list 12 permit tcp 192.168.0.0 0.0.0.255 any any

for example

are you sure inbound is not being blocked?

you don't have an access list on your Dialer1 interface with something like

access-list 100 deny tcp 192.168.0.0 0.0.0.255 any any

on the end

or just

access-list 100 deny ip any any




Gurner

http://www.divineparadox.co.uk

 

[gurner]

woops, the last 2 are irrelevant, as if NAT was running, and outbound on port 80 shouldn't be blocked back in

Gurner

http://www.divineparadox.co.uk

 

[dk87]

Don't forget port 53. Without DNS, you go nowhere!

 

[plshlpme]

did you configure the cisco yourself?
are you using dsl with pppoe?
it could be a configuration issue on the router with regards to the mtu