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Troubleshoot DHCP and Static IPs on FileWave Debian Appliances

What

FileWave provides pre-builtDebian Appliances,appliances quickfor tothese setup and peace of mind all should be well.  These currently include:components:

  • FileWave Server
  • Booster
  • IVS

Out of the box, FileWave AppliancesDebian areappliances configureduse DHCP by default. The same networking principles apply to use DHCP. You should note that these concepts in this article apply in general to anyother Debian installation,installations, but the Applicancescommands comeand inexamples here focus on FileWave appliances.

It is recommended that these are set to use static IPs, either from reconfiguring the Applianceappliance or bycreating way ofa DHCP reservations.reservation.

Why

FileWaveEvery cannot know in advance anycustomer network configuration, since each network will havehas its own uniqueaddressing setup.plan. Assign However,a staticstable IPaddress addressesduring provideinitial greatersetup reliability of service and faster data exchange withso the aimServer, toBooster, guaranteeor uptime.IVS does Asnot such,unexpectedly althoughmove thewhen Appliances are built witha DHCP configured,lease this should be addressed on initial configuration of the Appliance.changes.

Information

The following articles offer details for configuring static addresses on FileWave Appliances:

However,A itDHCP isreservation alsoassigns possiblethe chosen IP to usethe DHCP IP reservations, forcing an IP address perappliance MAC address; configuredaddress on the DHCP server instead.instead of configuring the address locally.

Troubleshooting

Example customer report to the FileWave Support Team:

Report

“"Despite having a DHCP IP reservationreservation, the Booster was not being assigned the definedexpected IP.”IP address."

Resolution

InFileWave this instance, working with the customer, the FileWaveTechnical Support teamfound helped identify 2two DHCP servers offering addresses foron thisthe same subnetsubnet. and onlyOnly one wasserver configured to assigncontained the correctreservation staticfor the expected IP.

RecommendationAvoid overlapping DHCP assignments

TheWhen followingmore considerationsthan shouldone beDHCP noted:server serves a subnet:

  • Where multiple DHCP servers are considered necessary to server a subnet, ensureGive each DHCP server is configured for a unique addressesaddress pool;pool. multipleDo DHCPnot let two servers should not be configured to provideoffer the same addresses inon one subnet.
Configure a given subnet.  Since only one DHCP server should provide any one singlereserved IP for a subnet, when mixing DHCP with static reservations, only one server can be configured to offer an IP for any oneappliance MAC address in a given subnet. The consequence of the above: for static reservations,on only add the MAC address for a device on one DHCP server for that subnet,subnet. which is handlingPlace the rangereservation ofon the server that owns the desired IP.IP range.

Overlapping address pools and relying on DHCP synchronisation is not recommended.

TheUse belowthese table shows someDebian commands thatto wereinspect usefulinterfaces, duringleases, theand troubleshootingneighboring of the described example issue:devices:

Command Description 
ip a

 Show network interfaces, includingIP IP,addresses, and MAC addresses, etc.addresses. 
ls /sys/class/net

 List just the names of the network interfacesinterface names. 

dhclient <name of network interface>

 Refresh the clientDHCP lease offor the providednamed network interfaceinterface. 

arp -a

 Display the network neighbourneighbor cachecache.

Examples:

'ip'The commandfollowing listingip a output shows two defined interfaces. In thethis example, 'ens192'ens192 is the active network interface for allcarries external traffic.

# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute 
       valid_lft forever preferred_lft forever
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:1d:1c:75 brd ff:ff:ff:ff:ff:ff
    altname enp11s0
    inet 10.85.1.9/24 brd 10.85.1.255 scope global ens192
       valid_lft forever preferred_lft forever

'lo' is the local loopback address

AssistsUse inthe displayinginterface output to find the MAC address if requiredneeded for a DHCP static IP reservationreservation.

TheTo belowlist commandinterface morenames simplistically displayswithout the namesaddress of the interfaces alone:details:

# ls /sys/class/net
ens192	lo

WereIf anthe appliance to pick up an 'incorrect' IP, it may be necessary to forcereceives the devicewrong toaddress, establishrenew athe newDHCP IPlease for the active interface. Using ens192 from the DHCP server.  Using the above example, the network interface name is 'ens192'.  Therefore the command would appear as:example:

# dhclient ens192

TheRun dhclient command should be ran as rootroot.

Thearp 'arp' command-a can behelp usefulidentify in identifying networkaddress conflicts. The belowThis example shows the DHCP/DNS server,server along withand two devices thatin the FileWaveappliance's Applianceneighbor is now aware.cache.

# arp -a
Linksys38496.home (10.85.1.1) at d8:9f:80:4c:24:67 [ether] on ens192
FW1063.home (10.85.1.230) at 5c:96:cf:db:62:3b [ether] on ens192
ml1063.home (10.85.1.136) at ac:d0:74:68:23:6d [ether] on ens192

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