Network troubleshooting

Network troubleshooting

Find open ports

lsof

Show all open IPv4/IPv6/both TCP ports:

# lsof -Pni 4TCP -sTCP:LISTEN
# lsof -Pni 6TCP -sTCP:LISTEN
# lsof -Pni      -sTCP:LISTEN

Show all open IPv4/IPv6/both addresses and applications listening on TCP port https(443):

# lsof -Pni 4TCP:443 -sTCP:LISTEN
# lsof -Pni 6TCP:443 -sTCP:LISTEN
# lsof -Pni  TCP:443 -sTCP:LISTEN

Testing connections from virtual interfaces / virtual IPs

Ping

# ping -I <your virtual ip> <destination>

On Solaris

# ping -sni <your virtual ip> <destination>

Traceroute

# traceroute -s <your virtual ip> <destination>

SSH

# ssh <user>@<destination> -o BindAddress=<your virtual ip>

Telnet

# telnet -b <your virtual ip> <destination>

Interface details

Linux

# ethtool -k eth1
Features for eth1:
rx-checksumming: on
tx-checksumming: on
	tx-checksum-ipv4: off [fixed]
	tx-checksum-ip-generic: on
	tx-checksum-ipv6: off [fixed]
	tx-checksum-fcoe-crc: off [fixed]
	tx-checksum-sctp: off [fixed]
scatter-gather: on
	tx-scatter-gather: on
	tx-scatter-gather-fraglist: off [fixed]
tcp-segmentation-offload: off
	tx-tcp-segmentation: off
	tx-tcp-ecn-segmentation: off [fixed]
	tx-tcp6-segmentation: off
udp-fragmentation-offload: off [fixed]
generic-segmentation-offload: off
generic-receive-offload: on
large-receive-offload: on
rx-vlan-offload: on
tx-vlan-offload: on
ntuple-filters: off [fixed]
receive-hashing: on
highdma: on
rx-vlan-filter: on [fixed]
vlan-challenged: off [fixed]
tx-lockless: off [fixed]
netns-local: off [fixed]
tx-gso-robust: off [fixed]
tx-fcoe-segmentation: off [fixed]
tx-gre-segmentation: off [fixed]
tx-ipip-segmentation: off [fixed]
tx-sit-segmentation: off [fixed]
tx-udp_tnl-segmentation: off [fixed]
fcoe-mtu: off [fixed]
tx-nocache-copy: off
loopback: off [fixed]
rx-fcs: off [fixed]
rx-all: off [fixed]
tx-vlan-stag-hw-insert: off [fixed]
rx-vlan-stag-hw-parse: off [fixed]
rx-vlan-stag-filter: off [fixed]
l2-fwd-offload: off [fixed]
busy-poll: off [fixed]