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Questions tagged [packet]

99 questions
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Accept ICMP packets (ping) with specific length - Iptable rules

I am going to filter Ping request to my server, and only accepts ping request with length 920. ping -l 920 serrveraddress I am using the following two command in iptables iptables -A INPUT -p icmp -m length --length 1:920 -j ACCEPT iptables -A…
rahram
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iptables connlimit: exclude multiple IP addresses

I have currently this IPTABLES command: iptables -A INPUT -s ! 192.168.0.2 -p tcp --syn -m connlimit [...] -j DROP As far as I know, such rule limit some number of connections following various parameters, except for 192.168.0.2 which is free to…
GPointer
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Split TCP packet - Data layer vs IPv4Layer

What is the different between split TCP packet in the Data layer compare to split the packet in IPv4Layer ?
ner aredob
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Viewing the packet-size of an incoming IP

I have been looking for a sulution to this for a few hours. after no avail im asking for help here. I need to watch my incoming packets by Size. in a format similar to: IP SIZE I have tried TCPDUMP but it does not give me the size of the actual…
JohnRong
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Understanding ARP traces during OS load

Consider the following ARP packets captured while a unix machine was booting. From the packets I understand that this machine whose MAC address is 00:22:22:22:22:22 is requesting information about which MAC address is the ip 192.160.100.20 assigned…
José D.
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Server sending packets every 5 minutes to 3 IPs

Been noticing in our firewall logs that three connections are being constantly established every 5 minutes from our web server and trying to send a packet to destination port 43 (whois port) cycling through all source ports (i.e. 59466, 59467,…
Anthony Miller
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UDP maximum segment size

Environment: I am writing a UDP client-server application. the path MTU between client and server is 1500 bytes (with only a wireless link between them, so this value is pretty much stable). My system set don't fragment bit by default, and on both…
schwannden
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VMWare-ESXi server dropping packets, shaky connection

I have a few virtual servers running on a VMWare-ESXi server. One of those is a mailserver running Windows server 2003, Has been running quite well for a while now. About 4 days ago, the mailserver runs beautifully for about 5-8 hours at which…
Thierry Blais
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Intel 82579LM Gbit Ethernet Controller - magic packet (WOL) right after ping is not working

I am experiencing a very annoying and mysterious behavior when sending magic packets (for Wake On LAN) shortly after pinging an Intel 82579LM GigaBit Ethernet Controller (the onboard ethernet controller of the Intel DQ67SW motherboard). So basically…
Wuhtzu
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Calculating the round trip time for ping packets

I am currently practicing for my network & communications course and have managed to confuse myself slightly on a question about packet round trip time. I have made a start but am now a bit stuck! Disclaimer: This is not homework, just a practice…
Pete Hamilton
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iptables : How to calculate how many bytes there're in a packet?

I'm working on a firewall and I would like to know how to calculate how many bytes there're in a packet or at least have an idea what the averages are. When I googled it, 1500 bytes was mentioned a lot but it appears to depend on the file size and…
Kris
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What is Reverse Gossip Transfer Protocol?

Playing with wireshark, I see a bunch of packets that say something like rgtp > https [ACK] Seq=???? Ack=?????? Win=????? Len=0 What is a Reverse Gossip Ttransfer Protocol? What is it used for, and by whom? p.s. Google takes me to…
Everyone
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What does "all packets that fall through to the default rule should be dropped" mean?

Does “all packets that fall through to the default rule should be dropped” mean that my iptables rule should drop everything at the start, like this? # Set the default policy to drop $IPT --policy INPUT DROP $IPT --policy OUTPUT DROP $IPT --policy…
Snow
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Computer sleep and wake up announcement on a network

I wonder if there's some sort of network packet that announces a computer going to sleep or waking up again. If not, can you think of reasons why this would be a bad idea?
sunside
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Bad mask /30 for address 10.1.1.3 || Cisco P.T

So basically I'm having this issue while trying to configure the serial of 3 routers (router0, router1, router2) on Cisco Packet Tracer I was able to configure both serials for router0 following this configuration: Router(config)#interface serial…
Roy Najar
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