Reg: dhcp service unresponsive frequently
Purva Rawan
purvar at cdac.in
Tue Jan 21 11:41:15 UTC 2020
1.Rsyslogd is used for logging.
2.We faced the same issue again and captured logs for tcpdump command as
suggested by you.It is observed that
unresponsive dhcp server received only request in tcpdump but the same request
is not logging in rsyslogd during the incident.
In working dhcp server ,we received both request and reply in tcpdump logs.
One more thing, we have ldap backend for dhcp configuration.
Here,I attached logs of tcpdump command for freeze dhcp service and working dhcp
service.
Regards,
Purva
On January 21, 2020 at 5:31 AM Bill Shirley <bill at c3po.polymerindustries.biz>
wrote:
>
> Run a tcpdump on the network interface looking for DHCP traffic. Are there
> any responses?
> # IPv4
> tcpdump -vv -e -n -i lan10 'portrange 67-68'
> # IPv6
> tcpdump -X -l -vv -e -n -i wifi 'portrange 546-547'
>
> Who is handling your logging? systemd-journald? rsyslogd?
>
> Bill
>
> On 1/20/2020 12:17 AM, Purva Rawan wrote:
>
> > >
> > Hi,
> >
> > We are using ISC-DHCP version is 4.1.1 on centos 6.4 .DHCP service
> > started becoming unresponsive once every week . The server itself is up and
> > running, but the DHCP service was unresponsive.We restarted the service. But
> > after few days dhcp service stopped working. No entries were written to the
> > dhcp log, and there was nothing helpful in any event log.We observed that
> > Load on server ,CPU utilization ,HDD utilization,network traffic are normal
> > during service get freeze.
> >
> > How to fix this issue?
> >
> > Regards,
> >
> > Purva
> >
> >
> >
> > For assimilation and dissemination of knowledge, visit cakes.cdac.in
> >
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16:30:41.329356 00:11:20:93:46:80 > 08:00:27:ba:ca:41, ethertype IPv4 (0x0800), length 590: (tos 0x0, ttl 255, id 25251, offset 0, flags [none], proto UDP (17), length 576)
10.208.8.1.bootps > 10.208.0.27.bootps: [udp sum ok] BOOTP/DHCP, Request from d8:d3:85:b4:7f:a8, length 548, hops 1, xid 0x89585500, secs 58014, Flags [none] (0x0000)
Gateway-IP 10.208.8.1
Client-Ethernet-Address d8:d3:85:b4:7f:a8
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
BR, Static-Route, Vendor-Option, Netbios-Name-Server
RN, RB
Lease-Time Option 51, length 4: 259200
Hostname Option 12, length 14: "ILOSGH011X3VE^@"
MSZ Option 57, length 2: 576
Vendor-Class Option 60, length 7: "CPQRIB3"
Client-ID Option 61, length 7: ether d8:d3:85:b4:7f:a8
16:30:41.795777 00:11:20:93:46:80 > 08:00:27:ba:ca:41, ethertype IPv4 (0x0800), length 328: (tos 0x0, ttl 255, id 25253, offset 0, flags [none], proto UDP (17), length 314)
10.208.16.1.bootps > 10.208.0.27.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:11:74:88:c3:cf, length 286, hops 1, xid 0xdebe4749, secs 1619, Flags [none] (0x0000)
Gateway-IP 10.208.16.1
Client-Ethernet-Address 00:11:74:88:c3:cf
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:11:74:88:c3:cf
Requested-IP Option 50, length 4: 10.208.17.246
MSZ Option 57, length 2: 576
Parameter-Request Option 55, length 7:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Hostname
Domain-Name, BR, NTP
Vendor-Class Option 60, length 12: "udhcp 1.20.2"
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16:30:06.019007 00:50:56:bc:03:b2 > 00:1f:29:5c:a2:62, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 328)
10.208.39.250.bootpc > 10.208.38.1.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:50:56:bc:03:b2, length 300, xid 0x67c1f617, Flags [none] (0x0000)
Client-IP 10.208.39.250
Client-Ethernet-Address 00:50:56:bc:03:b2
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Request
Hostname Option 12, length 12: "eci-slave3.1"
Parameter-Request Option 55, length 16:
Subnet-Mask, BR, Time-Zone, Classless-Static-Route
Domain-Name, Domain-Name-Server, Hostname, YD
YS, NTP, MTU, Option 119
Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, NTP
16:30:06.081563 00:1f:29:5c:a2:62 > 00:50:56:bc:03:b2, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 328)
10.208.38.1.bootps > 10.208.39.250.bootpc: [bad udp cksum d2dc!] BOOTP/DHCP, Reply, length 300, xid 0x67c1f617, Flags [none] (0x0000)
Client-IP 10.208.39.250
Your-IP 10.208.39.250
Client-Ethernet-Address 00:50:56:bc:03:b2
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: ACK
Server-ID Option 54, length 4: 10.208.38.1
Lease-Time Option 51, length 4: 20
Subnet-Mask Option 1, length 4: 255.255.254.0
Time-Zone Option 2, length 4: 23400
Domain-Name Option 15, length 12: "pune.cdac.in"
Domain-Name-Server Option 6, length 8: 10.208.0.11,10.208.11.16
Default-Gateway Option 3, length 4: 10.208.38.1
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