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[davevt31]

0 in the last octect is one of the most widely used scenarios for subnet masks.

[Clancy]

Davevt, I am familiar with seeing that as a local sub net but never as the WAN sub net mask. My WAN sub net mask is 255.255.255.255 but my LAN sub net is 255.255.255.0.  GVG reported that his WAN sub net (from his ISP) is 255.255.240.0. Because of my inexperience, seeing this threw me for a loop. Hence my query as to what his local sub net mask would be if his last octet is already 0.

I haven't finished my lessons yet but I did start them. Be afraid, Lycan. Be very afraid.

[KevTech]

Mine right now is 255.255.248.0

[Clancy]

Mine right now is 255.255.248.0

Is that your ISP sub net mask?

I need to hurry up with those lessons.

[davevt31]

( Trying to Help Clancy's Head explode    )

Mine is like the others 255.255.240.0.

Here's a tip for you studies- if the number in the subnet mask octet is 255 then the corresponding IP addresses have to be the same number...

(LOL, I haven't thought about any of this stuff in many many years- took the N+ test back in 2000 but have since replaced those brian cells with other more useful information)

[KevTech]

Is that your ISP sub net mask?

I need to hurry up with those lessons.

WAN - 255.255.248.0

LAN - 255.255.255.0

[Xinot]

WAN - 255.255.252.0
LAN - 255.255.255.0
 

[Clancy]

Thank you Xinot, thank you Kevtech, and thank YOU Davevt31 for making my head explode. It was just like one of those champagne poppers on New Years Eve: nothing but confetti. This is all very interesting stuff. Now I just need to apply myself in order to make sense of it all.

Thanks to Lycan for helping educate me.

[Lycan]

My Pleasure.

GVG - Motorola has issues with that modem. See how quick we are to blame ze router? for shame. 

[Fatman]

To let you in on the big secret, (and potentially one up Lycan) I will drop the critical difference between you and them Clancy, I bet you are using PPPoE and they are (probably) not.  PPPoE tends to use an empty netmask (hence all the 255s) because it is PPP traffic encapsulated over Ethernet and it is essentially unrouted.  This of course becomes less true with business class DSL where there are multiple public IPs to assign.

LAN subnets bear no relation to WAN subnets, due to the influence of NAT.  You are using a single IP on the WAN side, if this was direct routing you are right the size of the mask on both sides would be more important.

Now your lessons include PPP and PPPoE as well as IP subnetting.

[Clancy]

To let you in on the big secret, (and potentially one up Lycan) I will drop the critical difference between you and them Clancy, I bet you are using PPPoE and they are (probably) not.  PPPoE tends to use an empty netmask (hence all the 255s) because it is PPP traffic encapsulated over Ethernet and it is essentially unrouted.  This of course becomes less true with business class DSL where there are multiple public IPs to assign.

LAN subnets bear no relation to WAN subnets, due to the influence of NAT.  You are using a single IP on the WAN side, if this was direct routing you are right the size of the mask on both sides would be more important.

Now your lessons include PPP and PPPoE as well as IP subnetting.

Fatman, my head already exploded once. Thanks for piling on. And, yes, your IT Jedi skills are still sharp. I am running PPPoE. Has Lycan waved at you this morning? You know, the Italian "good luck" sign?

I susbcribe to Fiber Optic and it comes right out of the wall and into my router as if it were a LAN cable. Or WAN cable. No stinking modem for me since I ditched Cable internet as fast as was humanly possible when FiOS came riding into town. All of my cable boxes are tied to the router and it is somewhat humorous when speaking to tech support and I inform them that I no longer have one of their branded routers (the original was a DIR-615). You can almost see their head shaking over the phone line as they spout "Oh, I don't know about that...blah blah blah". My DIR-655 plays very nicely with their service. They expect you to pay for steak but only want you to cook hamburgers (I stole that line from some other guy who took the plunge and gave the "Italian good luck sign" to Mamma FiOS and their router). There are still many features on this router of which I have no idea what they are for. Like "static routing" for instance. Learning about sub-netting is but one step in the long process of taking your jobs away from you - since I will be so much better at it than you guys (in 20 or 30 years). The "Slingbox" uses port forwarding and sets itself up automatically. That works fine and dandy. I can watch my own TV from my Dad's house on his computer. What a complete waste of time! Do I hear snoring?
OK, I'm done.

[GVG]

My Pleasure.

GVG - Motorola has issues with that modem. See how quick we are to blame ze router? for shame. 

Could you expand on that? What exactly are the issues?  I own this modem so I have to decide if it is worth the money to replace it.  In other respects it works well, its very fast and works well with my Apple computers.

For some reason a few years ago when my ISP went to Ambit modems that were based on the Broadcom chipset, my Apple computers, as well as many other people who posted in Apples forums, noticed a drastic throughput reduction on those modems vs. the Texas Instrument chipset based modems. Windows PC's were not affected.  So I bought the 5120 because it was the only TI based modem left in Motorola's lineup.

The issue may have been resolved in the following years, but I don't know as I have not had another modem to test.

I have contacted a friend who works at the ISP to see if he can bring a modem by the house so I can see if it resolves the router freeze issue, and if the throughput issue has also been solved.

[Lycan]

It's usually a auto negotation issue with the modem. I'd ask for a replacement and see if the issue presists. Maybe ask for a different model or make.

[Fatman]

Has Lycan waved at you this morning? You know, the Italian "good luck" sign?

That is the morning howdoyado around here, we are a friendly bunch.

[GVG]

I tried another modem today, an Ambit. I ran it through the same test and it worked just fine. After rebooting the modem within 30 seconds I saw the router release and renew its IP, something I never saw it do with the Motorola modem.

Time for a new modem.