Dhcp Relay Agent And Acl On Sw 3750, DHCP Relay Agent and ACL on Sw 3750|
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Posted by Vimokh on September 4, 2006, 9:50 pm
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I have implemented ACL apply on SW 3750 and want to set DCHP Relay agent to forward to DCHP server that is different subnet. I have 2 VLAN . DCHP is on VLAN1 and want VLAN 2 can get ip from DCHP server on VLAN 1. So that I need to set up dchp relay agent on VLAN2 but my company have policy to apply ACL on VLAN 2 but it is not work to set up dchp relay agent. Anyone help me ,what about I need to do permitt rule on ACL to dchp relay agent work? Thanks and Regards; Vimokh | ||||||||||
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Posted by Merv on September 5, 2006, 5:58 am
Please log in for more thread options address 255.255.255.255, source UDP port 68 and destination UDP port 67 to send a DHCPDISCOVER request to the DHCP server. The DHCP server will then unicast a DHCP Offer packet back to the DHCP relay agent which will forward it to the DHCP client. The DHCP client will then sent a DHCP request to the Dhcp server indicating that it will use the offered IP address. The DHCP server will unicast a DHCP acknowledgement to the DHCP client. The access list smust be modified to permit the DHCP packets described. | ||||||||||
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Posted by Martin Gallagher on September 5, 2006, 5:55 pm
Please log in for more thread options On Tue, 05 Sep 2006 02:58:52 -0700, Merv wrote:
Also, clients renewing their lease unicast a DHCPREQUEST to the server that assigned them their lease. You need to account for this on an ingress ACL as well, i.e. ! permit udp <src addr & mask> eq 68 host <dhcp server addr> eq 67
!
-- Rgds, Martin | ||||||||||
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Posted by Vimokh on September 5, 2006, 10:16 pm
Please log in for more thread options Thank you all for your information.
Vimokh Martin Gallagher =E0=B9=80=E0=B8=82=E0=B8=B5=E0=B8=A2=E0=B8=99: > On Tue, 05 Sep 2006 02:58:52 -0700, Merv wrote:
> > > DHCP version 4 uses UDP with source IP address 0.0.0.0,destinaion
> > address 255.255.255.255, source UDP port 68 and destination UDP port 67 > > to send a DHCPDISCOVER request to the DHCP server. > > > > The DHCP server will then unicast a DHCP Offer packet back to the DHCP > > relay agent which will forward it to the DHCP client. > > > > The DHCP client will then sent a DHCP request to the Dhcp server > > indicating that it will use the offered IP address. > > > > The DHCP server will unicast a DHCP acknowledgement to the DHCP client. > > > > > > The access list smust be modified to permit the DHCP packets described. >
> Also, clients renewing their lease unicast a DHCPREQUEST to the server > that assigned them their lease. You need to account for this on an > ingress ACL as well, i.e. > > ! > permit udp <src addr & mask> eq 68 host <dhcp server addr> eq 67 > ! >=20 > --=20 > Rgds, > Martin | ||||||||||
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> address 255.255.255.255, source UDP port 68 and destination UDP port 67
> to send a DHCPDISCOVER request to the DHCP server.
>
> The DHCP server will then unicast a DHCP Offer packet back to the DHCP
> relay agent which will forward it to the DHCP client.
>
> The DHCP client will then sent a DHCP request to the Dhcp server
> indicating that it will use the offered IP address.
>
> The DHCP server will unicast a DHCP acknowledgement to the DHCP client.
>
>
> The access list smust be modified to permit the DHCP packets described.