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New Member

MAC and Vlan communication

I set up 5 Vlans using a 4507R and 3550 switches. I set up one DHCP server to supply all the Vlans with IP addresses. I am using a class A IP schema. The default Vlan has a 16 bits subnet mask and the other 4 have a 23 bits subnet mask. The trunk link is set up witht the 802.1q protocol. Everything is working fine, PCs are able to be authenticated from the Domain controllers as well as browse the network. The only problem I am having is with MAC computers. The MACs are able to get a DHCP address, but are not able to access resources located on a different vlan. The DNS, default gateway, and DHCP IP settings look OK. The MACs are able to ping the IP address of the Vlan interface they belong to, but not the default gateway IP address. Also, they are set up to use IP over AppleTalk. However, the only way MACs are able to ping other Vlans’ resources is when they are part of the default vlan (where all server resources reside). What do you think could be the problem? Thanks in advance for the help.

  • Other Network Infrastructure Subjects
5 REPLIES
Bronze

Re: MAC and Vlan communication

Two things:

1. Do a traceroute from a MAC to a server on another VLAN. See if the first hop is the default gateway.

2. Check the subnet mask on a MAC and see if it is consistent with what the DHCP server sends it.

HTH

Mark

New Member

Re: MAC and Vlan communication

Thanks for the help. I realized what I did wrong. Once I put the int. vlan ip address of each subnet as the default gate for the respective vlan the MAC computers were able to ping out of their Vlan. What puzzle me though is that I did not have to do it for the PCs. The PCs only needed the ip address of the feault vlan to go out!!

Thanks again.

Bronze

Re: MAC and Vlan communication

Maybe your PCs were running Router Discovery Protocol, while the MACS were not?

Mark

New Member

Re: MAC and Vlan communication

hey

can you guide me how can i implement this on my network. servers are connected to 2924s and all the 2924s are connected to 4006.

is it possible in 2924 or not.

thanx

kin

New Member

Re: MAC and Vlan communication

I am not too familiar with the 4006, but if your IOS support layer 3 switching, I am pretty sure it is possible. I would start by reading the IOS admin guide specific to your switch. Try to get your hands on a BCMSN book to know about the necessary concept such as V TP domain, protocol, and so on if don't already know that stuff. I am pretty sure that your 2924s will be able handled to configurations. Watch for the type of protocol you need to route and the type of service that needs to accessible across Vlans, and if possible try to test everything in a lab environment. I hope this help a little.

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