Talk:Default internal device network

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Conversation with PatrickDK on #dd-wrt

(02/13/2008 04:50:03 PM) dparker: PatrickDK: from this discussion and from looking at the UI, I'm now kind of uncertain as to the accuracy of what I'm saying on that page I made; why does the UI allow one to assign ports to a given vlan and yet also allow one to tag some members of that vlan and not others?  Isn't it true that there is a notion of a "default vlan" from the router's perspective where untagged packets are presumed to belong to it? 
(02/13/2008 04:51:25 PM) PatrickDK: what you mean, is the difference between vlan0 and untagged? 5* and just 5
(02/13/2008 04:51:34 PM) PatrickDK: I forget exactly the difference
(02/13/2008 04:51:53 PM) PatrickDK: but vlan0 means untagged on any other equipment
(02/13/2008 04:52:37 PM) PatrickDK: basically default setup is ports 0,1,2,3,4 are all untagged, and port 5 is tagged
(02/13/2008 04:52:58 PM) dparker: Well - read the text on that page - that's my current understanding of how it works.
(02/13/2008 04:53:09 PM) PatrickDK: what was the link?
(02/13/2008 04:53:26 PM) dparker:
(02/13/2008 04:57:22 PM) PatrickDK: dparker, as far as I know 5 = 5*
(02/13/2008 04:57:30 PM) PatrickDK: I haven't tested this, or confirmed, but it should be
(02/13/2008 04:58:11 PM) dparker: meaning just that port 5  accepts all packets, tagged or otherwise
(02/13/2008 04:58:15 PM) PatrickDK: but I think this actually means, if any untagged packets make it to port 5, they get tagged as vlan0
(02/13/2008 04:58:20 PM) PatrickDK: no
(02/13/2008 04:58:20 PM) dparker: ahh
(02/13/2008 04:58:21 PM) dparker: ok
(02/13/2008 04:58:22 PM) dparker: cus
(02/13/2008 04:58:38 PM) dparker: cuz I was thinking "default vlan" was just a function of *not* tagging something
(02/13/2008 04:58:52 PM) PatrickDK: on any other switch, yep
(02/13/2008 04:59:10 PM) dparker: well - where I'm doubting myself is that I'm assuming that tags map to vlans
(02/13/2008 04:59:12 PM) PatrickDK: default = untagged when working on any switch I have
(02/13/2008 04:59:28 PM) dparker: but the ui lets you have some ports on any vlan tagged or untagged
(02/13/2008 04:59:32 PM) dparker: that doesn't make sense to me
(02/13/2008 04:59:45 PM) PatrickDK: it gets confusing
(02/13/2008 04:59:52 PM) dparker: what am I missing?
(02/13/2008 04:59:54 PM) PatrickDK: I think the issue comes in when you do like
(02/13/2008 05:00:04 PM) PatrickDK: vlan0ports="0 1 2 3 5*"
(02/13/2008 05:00:12 PM) PatrickDK: vlan2ports="0 5t"
(02/13/2008 05:00:24 PM) dparker: the ui won't let you do that
(02/13/2008 05:00:24 PM) PatrickDK: in this, any packets untagged from port 0 should go to vlan0
(02/13/2008 05:00:33 PM) PatrickDK: well, the ui is not very smart
(02/13/2008 05:00:36 PM) dparker: the ui would let you do "0t 1 2 3 4 5*"
(02/13/2008 05:00:40 PM) dparker: which seems wrong
(02/13/2008 05:00:44 PM) PatrickDK: and is that way cause most people don't need overly complex stuff
(02/13/2008 05:00:46 PM) PatrickDK: no
(02/13/2008 05:00:55 PM) PatrickDK: that means packets going OUT port 0 get tagged
(02/13/2008 05:01:32 PM) dparker: hrm..... 
(02/13/2008 05:01:44 PM) PatrickDK: so a normal computer shouldn't be able to connect on port 0
(02/13/2008 05:01:45 PM) dparker: ohhhh
(02/13/2008 05:01:50 PM) PatrickDK: unless it was setup to use vlan0
(02/13/2008 05:02:08 PM) dparker: so you can set up a trunk to e.g. another router 
(02/13/2008 05:02:14 PM) PatrickDK: yep
(02/13/2008 05:02:17 PM) dparker: ahhhh
(02/13/2008 05:02:18 PM) dparker: ok
(02/13/2008 05:02:20 PM) PatrickDK: that I what I do on my setup
(02/13/2008 05:02:23 PM) dparker: now I have to ponder that
(02/13/2008 05:02:29 PM) PatrickDK: vlan0ports="0 1 2 3 4 5*"
(02/13/2008 05:02:32 PM) dparker: cuz I think the way I'm describing things is incorrect
(02/13/2008 05:02:34 PM) PatrickDK: vlan5ports="4t 5t"
(02/13/2008 05:02:50 PM) PatrickDK: so port 4 looks like a lan port
(02/13/2008 05:02:57 PM) PatrickDK: but I can also pass tagged packets on it to the router
(02/13/2008 05:03:09 PM) PatrickDK: and the router sees those tagged packets on vlan5
(02/13/2008 05:03:49 PM) PatrickDK: and if the router sends something out vlan5, it goes out over port 5, as tagged vlan5
(02/13/2008 05:04:00 PM) PatrickDK: in my case, this is the unencrypted wireless
(02/13/2008 05:04:34 PM) dparker: ok .... so I can have 5 5* and 5t, yes?
(02/13/2008 05:04:44 PM) PatrickDK: yep
(02/13/2008 05:04:59 PM) PatrickDK: I am not sure on the exact different of 5 and 5*
(02/13/2008 05:05:03 PM) dparker: in the former two cases, there is no tagging
(02/13/2008 05:05:36 PM) PatrickDK: I am not sure if 5* is vlan0 and 5 is eth0
(02/13/2008 05:05:37 PM) PatrickDK: or what
(02/13/2008 05:05:49 PM) PatrickDK: cause there is no vlan0 technically
(02/13/2008 05:05:54 PM) dparker: ahhh - ok
(02/13/2008 05:05:57 PM) PatrickDK: so it all is strange that they named it that way
(02/13/2008 05:06:26 PM) PatrickDK: I just know, it was set to 5*, and I used 5* :)
(02/13/2008 05:06:28 PM) dparker: so when other's have spoken of the default vlan, that's really *always* vlan0 
(02/13/2008 05:06:31 PM) PatrickDK: and it works
(02/13/2008 05:06:38 PM) PatrickDK: yep
(02/13/2008 05:06:44 PM) dparker: vlan0=internally untagged
(02/13/2008 05:06:49 PM) PatrickDK: yep
(02/13/2008 05:08:18 PM) dparker: ok - so - I think I have it - just one more q: in the UI the checkboxes that assign ports (mutex) to a vlan impart internal tagging except for vlan0.  The tagging buttons on the bottom export all that tagging to the outside (and in the case of vlan0, impart tagging to those packets as well) - yes?
(02/13/2008 05:09:51 PM) PatrickDK: dparker, your question is too complex :)
(02/13/2008 05:09:59 PM) dparker: sorry
(02/13/2008 05:10:27 PM) dparker: first: the checkboxes that assign ports to vlans - the ui is set up such that you can only put a port on one vlan
(02/13/2008 05:10:41 PM) dparker: the router in the unit has a vlan trunk to the switch
(02/13/2008 05:11:00 PM) PatrickDK: technically that is correct for vlan tagging
(02/13/2008 05:11:02 PM) dparker: I assume that the ui's mapping of ports to vlans arranges *internally* for tagging
(02/13/2008 05:11:11 PM) PatrickDK: cause your suppost to have trunk ports, and untagged ports
(02/13/2008 05:11:14 PM) PatrickDK: not mixed
(02/13/2008 05:11:25 PM) PatrickDK: but mixed is very usefull, when you are doing like voip
(02/13/2008 05:11:34 PM) dparker: woah - crap 
(02/13/2008 05:11:37 PM) dparker: that threw me
(02/13/2008 05:11:39 PM) PatrickDK: setup telephone to use like, vlan2, plug phone into port
(02/13/2008 05:12:09 PM) dparker: ok - you said that the checkboxes on the *bottom* only apply to *outbound* tagging
(02/13/2008 05:12:38 PM) PatrickDK: ya
(02/13/2008 05:12:51 PM) PatrickDK: basically
(02/13/2008 05:13:06 PM) PatrickDK: vlans work different ways, on incoming and outgoing
(02/13/2008 05:13:17 PM) PatrickDK: on outgoing, it puts, or removes the vlan tag
(02/13/2008 05:13:22 PM) PatrickDK: depending on if you want it or not
(02/13/2008 05:13:53 PM) PatrickDK: so I can port from one port that is tagged to vlan5, and thing coming in that can go out another port, as untagged, tagged vlan5, or tagged vlan2, or whatever
(02/13/2008 05:14:19 PM) PatrickDK: but incoming packets that are tagged, well, that is pretty simple
(02/13/2008 05:14:27 PM) PatrickDK: but if the incoming is untagged where do you place it?
(02/13/2008 05:14:36 PM) PatrickDK: that is what the * is for
(02/13/2008 05:14:39 PM) dparker: by "incoming" you mean "to the router"
(02/13/2008 05:14:43 PM) PatrickDK: yep
(02/13/2008 05:14:51 PM) PatrickDK: into the switch
(02/13/2008 05:14:55 PM) PatrickDK: not router really
(02/13/2008 05:15:12 PM) dparker: ok - but - port 5 is a trunk to the router
(02/13/2008 05:15:22 PM) PatrickDK: so I guess technically, it should be, vlan0ports="0* 1* 2* 3* 5*"
(02/13/2008 05:15:39 PM) PatrickDK: vlan1 is trunked
(02/13/2008 05:15:42 PM) PatrickDK: vlan0 is untagged
(02/13/2008 05:16:01 PM) PatrickDK: that still confuses me alittle
(02/13/2008 05:16:16 PM) dparker: heh that's an understatement
(02/13/2008 05:16:17 PM) PatrickDK: cause in my servers, I don't use vlan0, I just use eth0, and vlan1 vlan2 vlan2
(02/13/2008 05:16:37 PM) PatrickDK: na, I answered my own question about 5 the difference of 5 and 5* :)
(02/13/2008 05:16:44 PM) PatrickDK: and to explain default vlan better
(02/13/2008 05:16:49 PM) PatrickDK: to you :)
(02/13/2008 05:16:59 PM) PatrickDK: default vlan is the vlan untagged packets are put on :)
(02/13/2008 05:17:20 PM) PatrickDK: so lets say I have this more complex config, to demenstrate
(02/13/2008 05:17:39 PM) PatrickDK: lets put port 4 on vlans 0 and 1 untagged on both
(02/13/2008 05:17:49 PM) dparker: you can't do that in the ui
(02/13/2008 05:17:52 PM) PatrickDK: so packets from the router on lan and wan both go out port4 as untagged packets
(02/13/2008 05:18:03 PM) PatrickDK: no you can't (in the ui), but you can do it
(02/13/2008 05:18:24 PM) PatrickDK: your computer won't be able to tell what came from the lan or wan vlans at all
(02/13/2008 05:18:29 PM) dparker: yeah ok I get it
(02/13/2008 05:18:34 PM) PatrickDK: but your computer can talk back to ONE vlan
(02/13/2008 05:18:39 PM) PatrickDK: whatever vlan was configured with the *
(02/13/2008 05:18:47 PM) PatrickDK: as all untagged packets will be placed on that vlan
(02/13/2008 05:18:52 PM) dparker: which by default is vlan0
(02/13/2008 05:18:59 PM) dparker: vlan0 is by default * yes?
(02/13/2008 05:19:17 PM) PatrickDK: yep
(02/13/2008 05:19:29 PM) dparker: and unless you hit the command line, it will always be that way, right?
(02/13/2008 05:19:38 PM) PatrickDK: no
(02/13/2008 05:19:56 PM) PatrickDK: when you move the untagged vlan to any other port, in the ui, that moves it
(02/13/2008 05:20:07 PM) PatrickDK: you just can't do more than one in the ui
(02/13/2008 05:20:19 PM) PatrickDK: and there is hardly ever any point in doing so
(02/13/2008 05:21:13 PM) dparker: ok - thanks - I have enough to think through now