Cisco 2821 w/ 16 FastEthernet card and cable modem

[alkemyst]

OP here is a reference that may get you up and running:

http://www.dslreports.com/faq/8359

 

[alkemyst]

So, if the OP ever returns, disconnect the cable and do a show interface or show ip int brief and post your results.

My bet is up/down :whiste:

Hold on...this is a router...my bad.

On a router you can have an up / down condition if the interface is configured to be up but no cable it attached.

However on a switch this would never be the case except if possibily dealing with SVI's.

 

[MtnMan]

Hold on...this is a router...my bad.

On a router you can have an up / down condition if the interface is configured to be up but no cable it attached.

However on a switch this would never be the case except if possibily dealing with SVI's.

uhhhhhhh yea, that is what the OP clearly specified , and if you note, the examples I posted had IP addresses, which should also be a clue my examples are from a router.

 

[alkemyst]

Switches can have ips.

 

[alkemyst]

What model cable modem? Generic routers don't always behave like 'smart' ones. I will look more this morning as I will be in the office.

 

[MtnMan]

Switches can have ips.

Yes, on the VLAN

 

[spidey07]

Yes, on the VLAN

And on it's ports as well. That's what I posted in the 6509 example, a routed port, not a switchport.

 

[MtnMan]

And on it's ports as well. That's what I posted in the 6509 example, a routed port, not a switchport.

talk about trolling, a switch is normally considered a layer 2 device, unless you specify a layer 3 switch.

The OP is asking about a 2821 ROUTER, my responses were in regards to a router, so why in hell all the tangents and off topic crap about what can be done on a layer 3 switch?

 

[jlazzaro]

talk about trolling, a switch is normally considered a layer 2 device, unless you specify a layer 3 switch.

The OP is asking about a 2821 ROUTER, my responses were in regards to a router, so why in hell all the tangents and off topic crap about what can be done on a layer 3 switch?

dude, you need to take the Internet less seriously...start smoking weed or something.

the OP started with an ISR router, but it quickly turned into an interface status discussion and how it's represented differently across various devices. considering Mark hasn't returned to this thread to update us, there isn't really anywhere else to go.

 

[MtnMan]

dude, you need to take the Internet less seriously...start smoking weed or something.

the OP started with an ISR router, but it quickly turned into an interface status discussion and how it's represented differently across various devices. considering Mark hasn't returned to this thread to update us, there isn't really anywhere else to go.

A 2821 is an ISR router? Damn who knew. You assumed ISR router when you say 'linksys' but if you could read you would see the op was talking about a linksys cable modem

I have noticed the OP is MIA, wonder why.............. Maybe the off topic trolls sent him packing............. now where is the hell is your suggestion to solve his problem.......... I must have missed it cause you were off asking question on another off topic post.

The percentage of trolls in a technical forum are amazing, and do not represent people that actually know their ass from their hat. or the subforum should be renamed to "trolls that heard about networking".

 

[alkemyst]

MtnMan, you do seem a bit irate. Most of us were having an open discussion as the interface status is very different across the platforms.

However, in today's world most will assume outside the home/small business that a switch can operate at layer 3 as well.

 

[jlazzaro]

A 2821 is an ISR router? Damn who knew. You assumed ISR router when you say 'linksys' but if you could read you would see the op was talking about a linksys cable modem

lol, what? i can't tell if you're being sarcastic or thick...

either way, keep up the combative, ignorant comments and im sure you'll be on vacation soon enough.

 

[MarkXIX]

Wow fellas! Thanks for the help and the entertainment.

Haven't responded because I had to take a short two day trip to Aberdeen Proving Grounds. I'm in the hotel now and don't have access to the router.

If it helps, the 2821 ISR router has two built in 10/100/1000 ports and I'm trying to use one of them to place Linksys router on and set interface to DHCP. I only tried manual speed and duplex settings to try to get a connection after setting both to auto didn't work. The odd thing is, I get a link light at the router interface, but no link on the cable modem itself no matter what settings I use.

The odd thing is, if I plug it into one of the switch card interfaces, I get link, but don't recall what auto speed it linked at right now. Cable modem links up fine on the Linksys wireless router I originally had it plugged into. This is all using a manufactured 3ft. CAT5e cable straight out of the package and a few other manufactured cables I had lying around. I will get into the Linksys router and see if I can pull the speed and duplex from there since I'm running Tomato on it.

When I get home Friday I will try a few more things and update. Key point here though is to get the cable modem to link up and pull DHCP IP address from ISP. After that, I can figure out the NAT, firewall, etc.

 

[her209]

Haven't responded because I had to take a short two day trip to Aberdeen Proving Grounds. I'm in the hotel now and don't have access to the router.

Heh. What you there for?

 

[drebo]

Edit: NM. Didn't read the whole thread.

 

[drebo]

I'd say that depending on the model of the cable modem, you're looking at a speed/duplex mismatch. Cisco gigabit interfaces are funny sometimes in that they won't autonegotiate with a 100mbps link...I've got a number of 7206 routers (FE interfaces) plugged in to a 4500 switch (GigE interfaces) and they will not negotiate duplex at all. If I leave the GigE ports at auto, I get innundated with CDP messages about a duplex mismatch. If I set them to speed 100 duplex full on both sides, they work perfectly.

Your cable modem may only be capable of 100/half or even 10/half. Some older ones are definitely like that.

You can also try to issue no keepalive to the interface facing the cable modem and fake it...that'll force the interface into up/up mode, regardless of physical/line protocol.

Regarding some other comments, Ethernet interfaces do NOT show up/down if no cable is plugged in to them outside of GNS3. On real equipment, they show down/down, regardless of whether it's a switch or a router. Also, the link and line statuses of sh int and sh ip int brief are referencing the same things. In both cases (sh int and sh ip int) they reference physical link and line protocol. Physical link WILL NOT show "up" unless it actually is up on real equipment.

MtnMan: calling people who do this for a living "trolls" because their experience differs with your tinkering in GNS3 does not do much to endear you to the community. When you've got some seasoning under your belt, then you can come back and tell people off...but until then, your posts have spoken for themselves as to your actual level of knowledge. That level is not such that will garner you any respect among the more knowledgable people on this forum. There are plenty of very knowledgable people here and they will help to the best of their time/abilities...but cursing at them and calling them "trolls" isn't the best way to go about getting that aid.

 

[MarkXIX]

Heh. What you there for?

Looking at a thin client setup to see how to improve and implement at work.

 

[her209]

Looking at a thin client setup to see how to improve and implement at work.

Aww.. I thought you were there for some test firing of some ordnance.

 

[MarkXIX]

Aww.. I thought you were there for some test firing of some ordnance.

I wish. I may shoot this Cisco router though if I can't get this cable modem to link up on it.

 

[w0ss]

Regarding some other comments, Ethernet interfaces do NOT show up/down if no cable is plugged in to them outside of GNS3. On real equipment, they show down/down, regardless of whether it's a switch or a router. Also, the link and line statuses of sh int and sh ip int brief are referencing the same things. In both cases (sh int and sh ip int) they reference physical link and line protocol. Physical link WILL NOT show "up" unless it actually is up on real equipment.

I am going to drop this after this replay and ignore all other comments on this part of the thread.

I have checked on real equipment and what you say is factually incorrect. I have confirmed that on equipment I have in my physical possesion the link CAN show UP/Down. Notice I didn't say WILL. It appears to be IOS/platform dependent.

One thing I have learned working with Cisco is what it says on paper and what it actually does are not always one in the same.

 

[w0ss]

If it helps, the 2821 ISR router has two built in 10/100/1000 ports and I'm trying to use one of them to place Linksys router on and set interface to DHCP. I only tried manual speed and duplex settings to try to get a connection after setting both to auto didn't work. The odd thing is, I get a link light at the router interface, but no link on the cable modem itself no matter what settings I use.

If you get a link light on the router but not the cable modem that is an odd one. As others have mentioned speed/duplex is my thought. lowest common denominator in ethernet is 10/half I would start there. The other issue could be the Cable modem learning a mac address and not releasing it. I don't think that would affect link but could be a weird modem issue.

 

[MarkXIX]

Well, I got stuck in Dallas overnight, so won't get back home until tomorrow afternoon to take a second look and consider some of the recommendations made so far.