Dell OS10 Notes / Gotchas

Notes and gotchas for Dell OS10 (mostly for S4112F-ON switches)

Gotchas (as of OS10 10.5.1.4)

IPv6

• When using IPv6 with subnet masks between /64 and /128, be sure to set hardware l3 ipv6-extended-prefix with either 1024, 2048 or 3072 otherwise these addresses will not be routable. This setting requires a reboot to come into effect.

Serial Console

• The OS10 documentation for the S4112F-ON switch states support for 115200 baud rate, 8 data bits, and no parity. However, this functionality is achieved by a Debian process (agetty) with the following command /sbin/agetty --keep-baud 115200,38400,9600 ttyS0 vt220 and is spawned by jobs defined in /etc/init/ttyS0.conf and /etc/init/ttyS1.conf. As far as I can tell, ttyS0 is the standard serial console and ttyS1 is the USB serial console. If connected to a console server with a 9600 baud rate limitation, it will work if you send multiple BREAKS on the console (initially displaying garbage) which cycles through 115200,38400,9600.

BGP

• When defining as-path filters with ip as-path access-list 1 permit ASN and you're already familiar with Cisco as-path filters, the functionality differs in that it uses more standardised regex for path matching. For example, use ip as-path access-list 1 permit .*15169.* instead of _15169_.

• BGP neighbours have address-family ipv4 unicast and address-family ipv6 unicast immediately on creation. For IPv6 neighbours, you need to explicitly set no activate under address-family ipv4 unicast unles you want IPv4 prefixes to also be sent over the IPv6 session.

• If you are coming from a Cisco environment where you are using ttl-security hops 1 you will instead need to use ebgp-multihop 255 on the OS10 platform when defining a neighbour in order to achieve ttl security.

• Attaching communities to exported prefixes differs slightly from Cisco and can be achieved by defining an ip community-list and using this within your route-map. For example: ip community-list standard LIST1 permit ASN:TAG. Then use set comm-list LIST1 add in your route-map.

IP Access Lists

• If you are used to defining an ip access-list in a Cisco environment. You may not have been adding a deny after your permit lines due to there being an implicit deny. However, on the Dell platform there is no implicit deny so you will need to add a deny at the end of your list, for example: ip access-list ssh_inbound seq 100 deny tcp any any eq 22.