[HitchHiker]

Hi,

I recently got my first Mac, it's a G4 400Mhz PowerMac with 1Gb RAM and a 20Gb HD with OSX 10.4.6.

My current setup is -

Linksys Gateway - WRT54GS
Main PC - Wired connection
Mac - Wired Connection
Second PC - Wireless connection
PSP - Wireless connection


All system connect to the Gateway and can browse the internet. All systems are set up with the same details, except IP address obviously.

The problem is that the Mac just can't connect to some websites -

www.amazon.co.uk - Can't connect.
www.amazon.com - Connects fine.

www.photosig.com - Can't connect.


I've posted about the problem on Eurogamer just near the bottom of that thread before being advised to come here, so I've tried a few suggestions already.


Can anyone here help out?

Thanks,

HH.

[cla]

I had the same problem, turns out my ISP gave me an IP number ending with 255. A subnet mask of 255.255.255.0 makes this a broadcast address. Although I got another subnet mask, I suspect some routers freak out when handling IP's ending with 255. Hence the sporadical behaviour.


Hey, it's just a theory :>

[HitchHiker]

Nope, thats not the problem . . .


HH.

[besson3c]

Try a traceroute on those addressess to see where your connection is dying. Post the results if you need help interpreting them.

[HitchHiker]

Traceroute has started ...

traceroute to www.amazon.co.uk (87.238.81.129), 64 hops max, 40 byte packets
traceroute: sendto: No route to host
1 traceroute: wrote www.amazon.co.uk 40 chars, ret=-1
*traceroute: sendto: No route to host
traceroute: wrote www.amazon.co.uk 40 chars, ret=-1
*traceroute: sendto: No route to host
traceroute: wrote www.amazon.co.uk 40 chars, ret=-1

Lookup has started ...


; <<>> DiG 9.2.2 <<>> www.amazon.co.uk
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38068
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.amazon.co.uk. IN A

;; ANSWER SECTION:
www.amazon.co.uk. 59 IN A 87.238.85.129

;; Query time: 109 msec
;; SERVER: 158.43.128.1#53(158.43.128.1)
;; WHEN: Wed Jun 28 13:00:50 2006
;; MSG SIZE rcvd: 50

So traceroute fails but nslookup (dig) finds the IP address.


HH.

[ghporter]

It sounds like there's a problem with your ISP's DNS servers. Traceroute uses the servers in your configuration, but so does dig, so I'm puzzled... Does anyone have experience with both dig and traceroute and some explanation of this?

[HitchHiker]

If it was my ISP's DNS servers, wouldn't it also effect my PC web browser under windows too?



HH.

[ghporter]

It would if the PC had accessed the servers at the same time. They get updated periodically through a hierarchy from the "authoritative" servers (at the top) all the way down to secondary servers ISPs use as backups. If your primary server is busy, the secondary one is automatically selected-and they don't get updated simultaneously because one has to be active all the time.

However, I think this is a weirder issue than that. I'd go to terminal and issue "ifconfig /flushcache" (no quotes, of course) to clear the OS X DNS cache, then restart (just to be on the safe side). This will obviously clear your DNS cache, which might be corrupted-it may have bad or missing entries for the specific sites you're having problems with. Even if it isn't corrupted, clearing the cache gives you a known starting point.