View Full Version : School network problems (firewall?)

Apr 30, 2003, 02:24 PM
I'm having trouble using the WiFi network at my school with my PowerBook and AirPort Extreme. The OS recognises the wireless network, and I have no trouble getting online, but the only types of network activity that seem to work are Rendezvous printing and internet browsers. Other things - Sherlock, Mail, Watson, iChat - just don't make it through. I assume this is due to some kind of firewall.

Is there any way I can reconfigure my network settings so that I can use Mail at school the way I do at home?

May 5, 2003, 03:35 PM
Why hasn't anyone replied to this? Someone here must know whether this is possible. It's an annoying thing, and if I can fix it, I'd like to. Anyone?

May 5, 2003, 05:53 PM
this just doesn't make any sense if you can be on the internet looking at web pages but not be able to check mail or sign on to iChat or the likes

the only way that this could be a firewall is if those things are blocked for everyone, even those not on wireless.

May 5, 2003, 05:58 PM
double post by accident during some heavy traffic on macrumors...

May 5, 2003, 06:05 PM
Originally posted by shakespeare
Other things - Sherlock, Mail, Watson, iChat - just don't make it through. I assume this is due to some kind of firewall.

Is there any way I can reconfigure my network settings so that I can use Mail at school the way I do at home?

If the school has a firewall setup so certain activity is not allowed, then you're out of luck. Have you taken this to the IT department of the school in question?

May 5, 2003, 09:32 PM
Yeah, I should have specified this, it doesn't work when I'm wired, either. And I haven't talked to the IT department - they're not very clever, and I wanted to avoid an interaction with them; but I'll give it a shot. I know they recently sent us all an email that said they had blocked Kazaa because it was overcrowding the network; maybe this has something to do with that.

Thanks, guys.

May 5, 2003, 10:28 PM
i can't see how you can't use mail

they wouldn't block pop and smtp...can anyone else use a mail program? like outlook on pcs?

May 5, 2003, 10:42 PM
It is very simple, the firewall will only allow certain tcpip ports. (i.e. port 80 for browsing) Sherlock, iChat, Watson, all use different ports. There is no way that I know around this. (Well except web mail for e-mail.)

The printing is most likely done locally, so the firewall doesn't come into play....

(Also the case for the e-mail servers. In other words, you have to use the local e-mail servers to send and recieve, but they block port 110 (pop e-mail) to the network users so that you cannot download mail from another mail server.)

May 6, 2003, 07:20 AM
Your problem is that they are not running an open dhcp server. Check out the address that you are getting, it is probably a 169. address. Rendezvous is link-local, it only works on the subnet, it does not let you talk to any machines not directly connected (via wired or wireless) to you.

I would guess that you need to register your MAC address (ethernet hardware address) with the IT staff.

If you are trying to do this illegally, too bad, you won't be able to make it work. (not that it is impossible, but you would really need to know what you were doing).

If you are allowed on the network, you will need to work with the system.

Here is a quick verification

Last login: Mon May 5 20:51:13 on ttyp1
Welcome to Darwin!

In a terminal window type:
ifconfig en1

look for the line that says inet, that is your IP address, looking below, mine is

inet6 fe80::230:65ff:fe04:7b08%en1 prefixlen 64 scopeid 0x5
inet netmask 0xffffff00 broadcast
ether 00:30:65:04:7b:08
media: autoselect status: active
supported media: autoselect

Now check the routing tables:
netstat -rn
look for the line beginning with default

Routing tables

Destination Gateway Flags Refs Use Netif Expire
default UGSc 33 17 en1
10.0.1/24 link#5 UCS 1 0 en1 0:3:93:21:b0:81 UHLW 33 42245 en1 936 UHS 0 1 lo0 UH 9 125234 lo0
169.254 link#5 UCS 0 0 en1

If you address begins with 169, your screwed, if not try to see if you can talk to the router:

PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=20.805 ms
64 bytes from icmp_seq=1 ttl=64 time=2.39 ms
64 bytes from icmp_seq=2 ttl=64 time=3.223 ms
--- ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 2.39/8.806/20.805 ms