Users Guide

Setting Basic Network Information 231
The administrator can assign an IPv4 address or an IPv6 address to the OOB
management port and to any VLAN. By default, all ports (other than the OOB
port) are members of VLAN 1. If an IP address is assigned to VLAN 1, it is
possible to connect to the switch management interface by using any of the
front-panel switch ports. Assignment of an IP address to a VLAN associated to a
front panel interface is required to manage the Dell EMC Networking,
N1100-ON, N1500, N2000, and N2100-ON Series switches. The use of VLAN
1 for switch administration presents some security risks. Alternatively, a
management VLAN can be assigned as the native VLAN for a limited set of
front-panel ports and an IP address can be assigned to that VLAN. The use of
ACLs to restrict access to switch management is strongly recommended.
DHCP can be enabled on the OOB interface and VLAN interfaces
simultaneously, or they can be configured with static information. To
configure static address information on the default VLAN (or the
management VLAN), set the IP address and subnet mask on the VLAN
interface and configure a global default gateway for the switch to use front
panel interfaces (not the OOB interface). If a default gateway is configured
on routing interfaces (front-panel ports), then IP addresses not in the OOB
port subnet will not be reachable via the OOB port. The switch sends the
Vendor Class Identifier (Option 60) in the DHCP discover messages to assist
DHCP server administrators in distinguishing Dell EMC switches from other
devices in the network. This is a text string of the form DellEMC;<switch
model>;<firmware version>;<serial number> where the switch
model number is the specific switch model.
Adjusting the Management Interface MTU
When logging into the Dell EMC Networking N-Series switch using TCP, the
switch negotiates the TCP Maximum Segment Size (MSS) using the
minimum of the requested MSS or the MTU setting of the port. TCP packets
are transmitted from the switch with the DF (Don't Fragment) bit set in
order to receive notification of fragmentation from any transit routers. Upon
receiving an ICMP
Destination Unreachable, Fragmentation needed but DF
set
notification, the switch will reduce the MSS. However, many firewalls
block ICMP Destination Unreachable messages, which causes the destination
to request the packet again until the connection times out.
To resolve this issue, reduce the TCP MSS setting to a more appropriate value
on the local host or alternatively, set the system MTU to a smaller value.