Author Topic: DHCP issues (ip conflicts)  (Read 1093 times)

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Offline S.4

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DHCP issues (ip conflicts)
« on: January 16, 2019, 08:04:15 AM »
Dear sir, dear madam,

We get frequently reported that IP conflicts appear on our network.
I suspect this is related to the Avast for business anti virus product.

Steps to reproduce:
Setup sonicwall (TZ300 / NSA2600) with latest general firmware (6.5.1.3) as DHCP server.
Install avast for business with latest software version (version: 4.5 / 18.8.2546) on windows 10 pro (1803 / 17134.523), no domains, only WORKGROUP, local admin as user
Connect the two, with dynamic DHCP enabled on the windows client.
The client may receive an valid dhcp number when connecting.
Yet, when giving an ipconfig /release + ipconfig /renew, the dhcp entry in the dhcp table of dhcp server is lost.


If I install Avast for business, then the DHCP cannot be registered on the DHCP server (with wireshark):
3 DHCP offer, 1 DHCP ack, 5 DHCP offer

If I do not install Avast, then our DHCP server (sonicwall) can register DHCP entries after ipconfig /release + ipconfig /renew (with wireshark):
1 DHCP offer, 1 DHCP ack.

It looks like, when avast active, the DHCP Ack does not always arrive on the DHCP server.
Hence; DHCP table incomplete; network problems.

Avast support ticket is submitted.
No answers received so far and I am disappointed in the support portal.
For this reason, I also register on the forum.

I already tested with avast installed, but with all components turned off (all shields disabled) ; same issue / no dhcp entry.

Anybody experience with this problem?
Or possible solutions?

Best regards,

Stan

Offline Asyn

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Re: DHCP issues (ip conflicts)
« Reply #1 on: January 16, 2019, 08:28:24 AM »
Avast support ticket is submitted.
No answers received so far and I am disappointed in the support portal.
Hi Stan, post your ticket-ID.
Win 8.1 [x64] - Avast Premier 19.4.2374.BUC - CC 5.56 - MCS - EEK - FF ESR 60.6.1 [NS/AOS/uBO] - TB 60.6.1 [EM] - ACP/ASB/ASL.BC
Deutschsprachiger Bereich -> Avast Wissenswertes (Downloads, Anleitungen & Infos): https://forum.avast.com/index.php?topic=60523.0

Offline S.4

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Re: DHCP issues (ip conflicts)
« Reply #2 on: January 16, 2019, 08:34:29 AM »
07863580

Offline Asyn

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Re: DHCP issues (ip conflicts)
« Reply #3 on: January 16, 2019, 08:38:55 AM »
Win 8.1 [x64] - Avast Premier 19.4.2374.BUC - CC 5.56 - MCS - EEK - FF ESR 60.6.1 [NS/AOS/uBO] - TB 60.6.1 [EM] - ACP/ASB/ASL.BC
Deutschsprachiger Bereich -> Avast Wissenswertes (Downloads, Anleitungen & Infos): https://forum.avast.com/index.php?topic=60523.0